Thrips: Pests of Concern to China and the United States

Thrips are among the most important agricultural pests globally because of the damage inflicted by their oviposition, feeding, and ability to transmit plant viruses. Because of their invasiveness, a number of pest species are common to both China and the United States and present significant challenges to growers of a wide range of crops in both countries. Among the pest thrips common to both countries are four of the major global thrips pests, Frankliniella occidentalis （Pergande）, Scirtothrips dorsalis Hood, Thrips palmi Karny, and Thrips tabaci Lindeman. This review addresses characteristics that enable thrips to be such damaging pests and how biological attributes of thrips create challenges for their management. Despite these challenges, a number of successful management tactics have been developed for various cropping systems. We discuss some of these tactics that have been developed, including the use of cultural controls, biological controls, and judicious use of insecticides that do not disrupt overall pest management programs. The exchange of this type of information will help to facilitate management of pest thrips, especially in regions where species have recently invaded. A prime example is F. occidentalis, the western flower thrips, which is native to the United States, but has recently invaded China. Therefore, management tactics developed in the United States can be adapted to China. Because further success in management of thrips requires a thorough understanding of thrips ecology, we discuss areas of future research and emphasize the importance of collaboration among different countries to enhance our overall understanding of the biology and ecology of thrips and to improve management programs for these widespread pests.

Variation in Telial Formation of <i>Puccinia striiformis</i>in the United States

Puccinia striiformis, the causal agent of stripe rust in wheat, barley, and various wild grasses, produces urediniospores and teliospores on these primary or auxiliary hosts. Telial formation, which stops producing infectious urediniospores, is affected by various host and environmental conditions. However, it is not clear if variation exists among different isolates in the United States. To determine the differences in the pathogen population, 1423 isolates collected in the United States from 2013 to 2016 were tested for telial formation in the seedling stage at a diurnal temperature profile of 4&deg;C - 20&deg;C. The percentages of telial formation varied greatly among the isolates. Of the 1423 isolates, 62.97% produced telia with the percentages of telial formation ranging from 1% to 95% under the test conditions. The formation of telia was significantly affected by the year and the month when the isolates were collected. The epidemiological regions or states, host plants (wheat, barley, and grasses), and races of the isolates did not significantly affect telial formation. However, significant effects on telial formation were observed by interactions between year and region, year and race, month and region and among year, month, and region, as well as between year and month. The results showed that telial formation is a complex trait under the genetic control of the pathogen isolates for adaptation to different environments. Further studies are needed to identify genes involved in the formation of telia and the relationship of telial formation to the survival, aggressiveness, fitness, and evolution of the pathogen.

A Large Scale GIS Geodatabase of Soil Parameters Supporting the Modeling of Conservation Practice Alternatives in the United States

Water quality modeling requires across-scale support of combined digital soil elements and simulation parameters. This paper presents the unprecedented development of a large spatial scale (1:250,000) ArcGIS geodatabase coverage designed as a functional repository of soil-parameters for modeling and comparison of water quality outcomes in the United States. The set of target models include: SWAT (Soil and Water Assessment Tool), APEX (Agricultural Policy Environmental Extender), and ALMANAC (Agricultural Land Management Alternatives with Numerical Assessment Criteria). This development relies on the Digital General Soil Map (DGSM) as the source of soil information, and leverages on architectural design and associated tools created for a companion product at higher resolution from which also was extended a procedure for refilling a large number of missing derived parameters. Outlined by regional watershed layouts and supported by GIS land use layers, the core product is developed using the File Geodatabase (FGDB) data structure, which brings, via customized Python-based tools, the data directly into geoprocessing workflows. The FGDB implement efficiently stores spatial soil features, tabular model elements and linked relationships, while seamlessly providing the environment for the extraction, spatial analysis, and mapping of the models’ parameters. As an alternative, the composing spatial elements, polygons and multi-resolution rasters, and the models’ elements are offered as a file-folder system of data with completely Open Source formats. Finally, this geographic database coverage provides support for the traditional large-scale and harmonized application of the models as well as an alternative to the higher resolution companion for areas where this information is still under development.

An Assessment of Flowering Dogwood (<i>Cornus florida</i>L.) Decline in the Eastern United States

Cornus florida L. is one of the most numerous tree species in the Eastern United States (US). Multiple studies have reported localized declines in C. florida populations following the intro-duction of the destructive fungus Discula destructiva Redlin (dogwood anthracnose), but few, if any, have documented changes in C. florida populations across the species’ entire natural range. Thus, a current assessment of the C. florida population in the Eastern US and implications for future sustainability is warranted. Our study’s goal was to present C. florida population estimates across the natural range of the species (Little, 1971) in the Eastern US for two periods based on state-level forest land inventories conducted by the US Department of Agriculture Forest Service, Forest Inventory and Analysis (FIA) program. Rangewide, C. florida populations declined by approximately 49% over the time periods studied. At the State level, population declines occurred in 17 out of 30 states and biomass declines occurred in 20 out of 30 states studied. While declines were widespread in the substate units surrounding the Appalachians, the largest declines appeared to be centered within the Appalachian ecoregion.

Bowen Ratio Energy Balance Measurement of Carbon Dioxide (CO₂) Fluxes of No-Till and Conventional Tillage Agriculture in Lesotho

Global food demand requires that soils be used intensively for agriculture, but how these soils are managed greatly impacts soil fluxes of carbon dioxide (CO2). Soil management practices can cause carbon to be either sequestered or emitted, with corresponding uncertain influence on atmospheric CO2 concentrations. The situation is further complicated by the lack of CO2 flux measurements for African subsistence farms. For widespread application in remote areas, a simple experimental methodology is desired. As a first step, the present study investigated the use of Bowen Ratio Energy Balance (BREB) instrumentation to measure the energy balance and CO2 fluxes of two contrasting crop management systems, till and no-till, in the lowlands within the mountains of Lesotho. Two BREB micrometeorological systems were established on 100-m by 100-m sites, both planted with maize (Zea mays) but under either conventional (plow, disk-disk) or no-till soil mangement systems. The results demonstrate that with careful maintenance of the instruments by appropriately trained local personnel, the BREB approach offers substantial benefits in measuring real time changes in agroecosystem CO2 flux. The periods where the two treatments could be compared indicated greater CO2 sequestration over the no-till treatments during both the growing and non-growing seasons.

Exploring the genetic control of sweat gland characteristics in beef cattle for enhanced heat tolerance

Background Thermal stress in subtropical regions is a major limiting factor in beef cattle production systems with around$369 million being lost annually due to reduced performance.Heat stress causes numerous physiological and behavioral disturbances including reduced feed intake and decreased production levels.Cattle utilize various physiological mechanisms such as sweating to regulate internal heat.Variation in these traits can help identify genetic variants that control sweat gland properties and subsequently allow for genetic selection of cattle with greater thermotolerance.Methods This study used 2,401 Brangus cattle from two commercial ranches in Florida.Precise phenotypes that contribute to an animal's ability to manage heat stress were calculated from skin biopsies and included sweat gland area,sweat gland depth,and sweat gland length.All animals were genotyped with the Bovine GGP F250K,and BLUPF90 software was used to estimate genetic parameters and for Genome Wide Association Study.Results Sweat gland phenotypes heritability ranged from 0.17 to 0.42 indicating a moderate amount of the phenotypic variation is due to genetics,allowing producers the ability to select for favorable sweat gland properties.A weighted single-step GWAS using sliding 10 kb windows identified multiple quantitative trait loci(QTLs)explaining a significant amount of genetic variation.QTLs located on BTA7 and BTA12 explained over 1.0%of genetic variance and overlap the ADGRV1 and CCDC168 genes,respectively.The variants identified in this study are implicated in processes related to immune function and cellular proliferation which could be relevant to heat management.Breed of Origin Alleles(BOA)were predicted using local ancestry in admixed populations(LAMP-LD),allowing for identification of markers'origin from either Brahman or Angus ancestry.A BOA GWAS was performed to identify regions inherited from particular ancestral breeds that might have a significant impact on sweat gland phenotypes.Conclusions The results of the BOA GWAS indicate that both Brahman and Angus alleles contribute positively to sweat gland traits,as evidenced by favorable marker effects observed from both genetic backgrounds.Understanding and utilizing genetic traits that confer better heat tolerance is a proactive approach to managing the impacts of climate change on livestock farming.

Is magnesium deficiency the major cause of needle chlorosis of Pinus taeda in Brazil?

Needle chlorosis(NC)in Pinus taeda L.systems in Brazil becomes more frequent after second and third harvest rotation cycles.In a study to identify factors contributing to yellowing needle chorosis(YNC),trees were grown in soils originating from contrasting parent materials,and soils and needles(whole,green and chlorotic portions)from 1-and 2-year-old branches and the first and second needle flush release at four sites with YNC on P.taeda were analyzed for various elements and properties.All soils had very low base levels(Ca^(2+),Mg^(2+)and K^(+))and P,suggesting a possible lack of multiple elements.YNC symptoms started at needle tips,then extended toward the needle base with time.First flush needles had longer portions with YNC than second flush needles did.Needles from the lower crown also had more symptoms along their length than those higher in the canopy.Symptoms were similar to those reported for Mg.In chlorotic portions,Mg and Ca concentrations were well below critical values;in particular,Mg levels were only one third of the critical value of 0.3 g kg^(-1).Collectively,results suggest that Mg deficiency is the primary reason for NC of P.taeda in various parent soils in Brazil.

A glycine-rich nuclear effector VdCE51 of Verticillium dahliae suppresses plant immune responses by inhibiting the accumulation of GhTRXH2

Verticillium dahliae is an important soil-borne fungal pathogen that causes great yield losses in many cash crops.Effectors of this fungus are known to regulate plant immunity but the mechanism much remains unclear.A glycine-rich nuclear effector,VdCE51,was able to suppress immune responses in tobacco against Botrytis cinerea and Sclerotinia sclerotiorum.This effector was a required factor for full virulence of V.dahliae,and its nuclear localization was a requisite for suppressing plant immunity.The thioredoxin GhTRXH2,identified as a positive regulator of plant immunity,was a host target of VdCE51.Our findings show a virulence regulating mechanism whereby the secreted nuclear effector VdCE51 interferes with the transcription of PR genes,and the SA signaling pathway by inhibiting the accumulation of GhTRXH2,thus suppressing plant immunity.

Differential regulation of protein synthesis in skeletal muscle and liver of neonatal pigs by leucine through an mTORC1-dependent pathway

Neonatal growth is characterized by a high protein synthesis rate that is largely due to an enhanced sensitivity to the postprandial rise in insulin and amino acids, especially leucine. The mechanism of leucine＇s action in vivo is not well understood. In this study, we investigated the effect of leucine infusion on protein synthesis in skeletal muscle and liver of neonatal pigs. To evaluate the mode of action of leucine, we used rapamycin, an inhibitor of mammalian target of rapamycin （mTOR） complex-1 （mTORC1）. Overnight-fasted 7-day-old piglets were treated with rapamycin for 1 hour and then infused with leucine （400 μmol·kg^-1·h^-1） for 1 hour. Leucine infusion increased the rate of protein synthesis, and ribosomal protein S6 kinase 1 （S6K1） and eukaryotic initiation factor （elF） 4E-binding protein-1 （4E-BP1） phosphorylation in gastrocnemius and masseter muscles （P 〈 0.05）, but not in the liver. The leucine-induced stimulation of protein synthesis and S6K1 and 4E-BP1 phosphorylation were completely blocked by rapamycin, suggesting that leucine action is by an mTORC1-dependent mechanism. Neither leucine nor rapamycin had any effect on the activation of the upstream mTQRC1 regulators, AMP-activated protein kinase and protein kinase B, in skeletal muscle or liver. The activation of elF2α and elongation factor 2 was not affected by leucine or rapamycin, indicating that these two pathways are not limiting steps of leucine-induced protein synthesis. These results suggest that leucine stimulates muscle protein synthesis in neonatal pigs by inducing the activation of mTORC1 and its downstream pathway leading to mRNA translation.

Overexpression of an ABA biosynthesis gene using a stress-inducible promoter enhances drought resistance in petunia

The response of plants to drought stress includes reduced transpiration as stomates close in response to increased abscisic acid(ABA)concentrations.Constitutive overexpression of 9-cis-epoxycarotenoid dioxygenase(NCED),a key enzyme in ABA biosynthesis,increases drought resistance,but causes negative pleiotropic effects on plant growth and development.We overexpressed the tomato NCED(LeNCED1)in petunia plants under the control of a stress-inducible promoter,rd29A.Under water stress,the transgenic plants had increased transcripts of NCED mRNA,elevated leaf ABA concentrations,increased concentrations of proline,and a significant increase in drought resistance.The transgenic plants also displayed the expected decreases in stomatal conductance,transpiration,and photosynthesis.After 14 days without water,the control plants were dead,but the transgenic plants,though wilted,recovered fully when re-watered.Well-watered transgenic plants grew like non-transformed control plants and there was no effect of the transgene on seed dormancy.

Rangelands of Central Asia:challenges and opportunities

Rangelands of Central Asia (referring to Kazakhstan, Kyrgyzstan, Tajikistan, Turkmenistan and Uzbekistan in this study), the largest contiguous area of grazed land in the world, serve as an important source of livelihood for pastoral and agro-pastoral communities in this region. They also play an important role in absorbing CO2 as a global carbon sink. However, unsustainable management of rangelands has led to their degradation hugely by downgrading their potential agro-ecological, environmental and socio-economical roles. This paper reviewed the rangeland degradation in Central Asia, a topic which so far has received only scant coverage in the international scientific literature. It also provided examples of successful experiences and outlined possible options that land managers can adopt to enhance the sustainable management of these vast degraded rangelands. The experiences and lessons described in this paper may also be relevant for other degraded rangeland areas, especially in the developing countries. The causes of rangeland degradation within the Central Asian region are numerous, complex and inter-related. Therefore, while addressing the factors associated with improper rangeland management may shed some light on the causes of rangeland degradation, the scope of this paper would not be all-encompassing for the major causes of degradation. There is a need to develop and widely apply the viable and locally accepted and adapted packages of technical, institutional and policy options for sustainable rangeland management. Incentivizing the collective action of small-scale pastoralists who group together to facilitate access to remote pastures can reduce the degree of overgrazing within community pastures, such as those near the settlements. We also found that migratory grazing through pooling of resources among small-scale pastoralists can increase household income. After their independence, most Central Asian countries adopted various rangeland tenure arrangements. However, the building of enhanced capacities of pasture management and effective local rangeland governance structures can increase the likelihood, which will be sustainable and equitable. Finally, this paper presented several promising technical options, aiming at reversing the trend of rangeland degradation in Central Asia.

Regulation of protein degradation pathways by amino acids and insulin in skeletal muscle of neonatal pigs

Background： The rapid gain in lean mass in neonates requires greater rates of protein synthesis than degradation. We previously delineated the molecular mechanisms by which insulin and amino acids, especially leucine, modulate skeletal muscle protein synthesis and how this changes with development. In the current study, we identified mechanisms involved in protein degradation regulation. In experiment 1,6- and 26-d-old pigs were studied during 1） euinsulinemic-euglycemic-euaminoacidemic, 2） euinsulinemic-euglycemiohyperaminoacidemic, and 3） hyperinsulinemic-euglycemic-euaminoacidemic clamps for 2 h. In experiment 2, 5-d-old pigs were studied during 1） euinsulinemic-euglycemic-euaminoacidemic-euleucinemic, 2） euinsulinemic-euglycemic-hypoaminoacidemic- hyperleucinemic, and 3） euinsulinemic-euglycemic-euaminoacidemic-hyperleucinemic clamps for 24 h. We determined in muscle indices of ubiquitin-proteasome, i.e., atrogin-1 （MAFbx） and muscle RING-finger protein-1 （MuRF1） and autophagy-lysosome systems, i.e., unc51-1ike kinase 1 （UKL1）, microtubule-associated protein light chain 3 （LC3）, and lysosomal-associated membrane protein 2 （Lamp-2）. For comparison, we measured ribosomal protein 56 （rpS6） and eukaryotic initiation factor 4E （elF4E） activation, components of translation initiation. Results： Abundance of atrogin-1, but not MuRF1, was greater in 26- than 6-d-old pigs and was not affected by insulin, amino acids, or leucine. Abundance of ULK1 and LC3 was higher in younger pigs and not affected by treatment. The LC3-11/LC3-1 ratio was reduced and ULK1 phosphorylation increased by insulin, amino acids, and leucine. These responses were more profound in younger pigs. Abundance of Lamp-2 was not affected by treatment or development. Abundance of elF4E, but not rpS6, was higher in 6- than 26-d-old-pigs but unaffected by treatment. Phosphorylation of elF4E was not affected by treatment, however, insulin, amino acids, and leucine stimulated rpS6 phosphorylation, and the responses decreased with development.

Difference in volatile profile between pericarp tissue and locular gel in tomato fruit

Aroma, a complex mixture of volatile compounds, plays an important role in the perception and acceptability of tomato products by consumers. Numerous studies have reported volatile profiles in tomatoes based on measurement of the whole fruit or pericarp tissue, however, little is understood regarding the volatile compositions in the inner tissues. The objective of this study was to investigate the differences in volatile profile between pericarp tissue and Iocular gel in tomato fruit. Based on HS-SPME-GC-MS analysis, totally 42 volatile compounds were detected in FL 47 and Tasti-Lee tomato fruits. Regardless of cultivars, a substantial higher concentration of total volatile compounds was observed in pericarp than that in/ocular gel, associated with higher levels of aldehydes, hydrocarbons, and nitrogen compounds. Pericarp tissue possessed higher levels of cis-3-hexenal, hexanal, heptanal, octanal, nonanal, cymene, terpinolene, undecane, dodecane, 2-phenylethanol, 6-methyl-5-hepten-2-one, 2-methylbutyl acetate, 1-nitro-pentane, and 1-nitro-2-phenylethane, while the abundances of 2-methylpropanal, butanal, 2-methylbutanal, 2-methyl-2-butenal, 2-methylpropanol, 3-methylbutanol, 2-methylbutanol, and 2-butanone were higher in Iocular gel. Principal component analysis （PCA） and cluster analysis using GC-MS and electronic nose （E-nose） data discriminated the two tissues.

Small RNAs, emerging regulators critical for the development of horticultural traits

Small RNAs(sRNAs)have been recently recognized as key genetic and epigenetic regulators in various organisms,ranging from the modification of DNA and histone methylations to the modulation of the abundance of coding or non-coding RNAs.In plants,major regulatory sRNAs are classified as respective microRNA(miRNA)and small interfering RNA(siRNA)species,with the former primarily engaging in posttranscriptional regulation while the latter in transcriptional one.Many of these characterized sRNAs are involved in regulation of diverse biological programs,processes,and pathways in response to developmental cues,environmental signals/stresses,pathogen infection,and pest attacks.Recently,sRNAs-mediated regulations have also been extensively investigated in horticultural plants,with many novel mechanisms unveiled,which display far more mechanistic complexity and unique regulatory features compared to those studied in model species.Here,we review the recent progress of sRNA research in horticultural plants,with emphasis on mechanistic aspects as well as their relevance to trait regulation.Given that major and pioneered sRNA research has been carried out in the model and other plants,we also discuss ongoing sRNA research on these plants.Because miRNAs and phased siRNAs(phasiRNAs)are the most studied sRNA regulators,this review focuses on their biogenesis,conservation,function,and targeted genes and traits as well as the mechanistic relation between them,aiming at providing readers comprehensive information instrumental for future sRNA research in horticulture crops.

A NAC transcription factor, NOR-like1, is a new positive regulator of tomato fruit ripening

Ripening of the model fruit tomato(Solanum lycopersicum)is controlled by a transcription factor network including NAC(NAM,ATAF1/2,and CUC2)domain proteins such as No-ripening(NOR),SlNAC1,and SlNAC4,but very little is known about the NAC targets or how they regulate ripening.Here,we conducted a systematic search of fruit-expressed NAC genes and showed that silencing NOR-like1(Solyc07g063420)using virus-induced gene silencing(VIGS)inhibited specific aspects of ripening.Ripening initiation was delayed by 14 days when NOR-like1 function was inactivated by CRISPR/Cas9 and fruits showed obviously reduced ethylene production,retarded softening and chlorophyll loss,and reduced lycopene accumulation.RNA-sequencing profiling and gene promoter analysis suggested that genes involved in ethylene biosynthesis(SlACS2,SlACS4),color formation(SlGgpps2,SlSGR1),and cell wall metabolism(SlPG2a,SlPL,SlCEL2,and SlEXP1)are direct targets of NOR-like1.Electrophoretic mobility shift assays(EMSA),chromatin immunoprecipitation-quantitative PCR(ChIP-qPCR),and dual-luciferase reporter assay(DLR)confirmed that NOR-like1 bound to the promoters of these genes both in vitro and in vivo,and activated their expression.Our findings demonstrate that NOR-like1 is a new positive regulator of tomato fruit ripening,with an important role in the transcriptional regulatory network.

Sensing of Moisture Content of In-Shell Peanuts by NIR Reflectance Spectroscopy

It was found earlier that moisture content (MC) of intact kernels of grain and nuts could be determined by Near Infra Red (NIR) reflectance spectrometry. However, if the MC values can be determined while the nuts are in their shells, it would save lot of labor and money spent in shelling and cleaning the nuts. Grain and nuts absorb low levels of NIR, and when NIR radiation is incident on them, a substantial portion of the radiation is reflected back. Thus, studying the NIR reflectance spectra emanating from in-shell peanuts, an attempt is made for the first time to determine the MC of in-shell peanuts. In-shell peanuts of two different market types, Virginia and Valencia, were conditioned to different moisture levels between 6% and 26% (wet basis), and separated into calibration and validation groups. NIR absorption spectral data from 1000 nm to 2500 nm in 1 nm intervals were collected from both groups. Measurements were obtained on 30 replicates within each moisture level. Reference MC values for each moisture level in these groups were obtained using standard air-oven method. Partial Least Square (PLS) analysis was performed on the calibration data, and prediction models were developed. The Standard Error of Calibration (SEC), and R2 of the calibration models were computed to select the best calibration model. The selected models were used to predict the moisture content of peanuts in the validation sets. Predicted MC values of the validation samples were compared with their standard air-oven moisture values. Goodness of fit was determined based on the lowest Standard Error of Prediction (SEP) and highest R2 value obtained for the prediction models. The model, with reflectance plus normalization spectral data with an SEP of 0.74 for Valencia and 1.57 for Virginia type in-shell peanuts was selected as the best model. The corresponding R2 values were 0.98 for both peanut types. This work establishes the possibility of sensing MC of intact in-shell peanuts by NIR reflectance method, and would be useful for the peanut and allied industries.

Expression of the N-terminal 99 Amino Acids of Yeast Ribosomal Protein L3 in Transgenic Wheat Confers Resistance to Fusarium Head Blight

Fusarium head blight (FHB) is a worldwide disease for wheat or barley. The contamination of important agricultural products with the trichothecene mycotoxins such as deoxynivalenol (DON) or 4,15-diacetoxyscirpe-

PhERF2,an ethylene-responsive element binding factor,plays an essential role in waterlogging tolerance of petunia

Ethylene-responsive element binding factors(ERFs)are involved in regulation of various stress responses in plants,but their biological functions in waterlogging stress are largely unclear.In this study,we identified a petunia(Petunia×hybrida)ERF gene,PhERF2,that was significantly induced by waterlogging in wild-type(WT).To study the regulatory role of PhERF2 in waterlogging responses,transgenic petunia plants with RNAi silencing and overexpression of PhERF2 were generated.Compared with WT plants,PhERF2 silencing compromised the tolerance of petunia seedlings to waterlogging,shown as 96%mortality after 4 days waterlogging and 14 days recovery,while overexpression of PhERF2 improved the survival of seedlings subjected to waterlogging.PhERF2-RNAi lines exhibited earlier and more severe leaf chlorosis and necrosis than WT,whereas plants overexpressing PhERF2 showed promoted growth vigor under waterlogging.Chlorophyll content was dramatically lower in PhERF2-silenced plants than WT or overexpression plants.Typical characteristics of programmed cell death(PCD),DNA condensation,and moon-shaped nuclei were only observed in PhERF2-overexpressing lines but not in PhERF2-RNAi or control lines.Furthermore,transcript abundances of the alcoholic fermentation-related genes ADH1-1,ADH1-2,ADH1-3,PDC1,and PDC2 were reduced in PhERF2-silenced plants,but increased in PhERF2-overexpressing plants following exposure to 12-h waterlogging.In contrast,expression of the lactate fermentation-related gene LDH was up-regulated in PhERF2-silenced plants,but downregulated in its overexpressing plants.Moreover,PhERF2 was observed to directly bind to the ADH1-2 promoter bearing ATCTA motifs.Our results demonstrate that PhERF2 contributes to petunia waterlogging tolerance through modulation of PCD and alcoholic fermentation system.

Diversity and redundancy of the ripening regulatory networks revealed by the fruitENCODE and the new CRISPR/Cas9 CNR and NOR mutants

Tomato is considered as the genetic model for climacteric fruits,in which three major players control the fruit ripening process:ethylene,ripening transcription factors,and DNA methylation.The fruitENCODE project has now shown that there are multiple transcriptional circuits regulating fruit ripening in different species,and H3K27me3,instead of DNA methylation,plays a conserved role in restricting these ripening pathways.In addition,the function of the core tomato ripening transcription factors is now being questioned.We have employed CRISPR/Cas9 genome editing to mutate the SBP-CNR and NAC-NOR transcription factors,both of which are considered as master regulators in the current tomato ripening model.These plants only displayed delayed or partial non-ripening phenotypes,distinct from the original mutant plants,which categorically failed to ripen,suggesting that they might be gain-of-function mutants.Besides increased DNA methylation genome-wide,the original mutants also have hyper-H3K27me3 in ripening gene loci such as ACS2,RIN,and TDR4.It is most likely that multiple genetic and epigenetic factors have contributed to their strong non-ripening phenotypes.Hence,we propose that the field should move beyond these linear and twodimensional models and embrace the fact that important biological processes such as ripening are often regulated by highly redundant network with inputs from multiple levels.

Molecular detection of Xanthomonas oryzae pv.oryzae, Xanthomonas oryzae pv. oryzicola, and Burkholderia glumae in infected rice seeds and leaves

The polymerase chain reaction(PCR) is particularly useful for plant pathogen detection. In the present study, multiplex PCR and SYBR Green real-time PCR were developed to facilitate the simultaneous detection of three important rice pathogens, Xanthomonas oryzae pv.oryzae, X. oryzae pv. oryzicola, and Burkholderia glumae. The unique PCR primer sets were designed from portions of a putative glycosyltransferase gene of X. oryzae pv. oryzae, an Avr Rxo gene of X. oryzae pv. oryzicola, and an internal transcribed spacer(ITS) sequence of B. glumae. Using a multiplex PCR assay, X. oryzae pv. oryzae, X. oryzae pv. oryzicola, and B. glumae were detected in one PCR reaction that contained the newly developed primer set mix. Using SYBR Green real-time PCR assays, X. oryzae pv. oryzae, X. oryzae pv. oryzicola, and B. glumae were detected at 1, 1, and 10 fg μL-1, respectively. These newly designed molecular assays are sensitive and could be reliable tools for pathogen detection and disease forecasting.