段宝忠教授受邀担任Frontiers in Plant Science客座副主编

近日,大理大学药学院段宝忠教授受邀担任植物学领域国际前沿期刊Frontiers in Plant Science客座副主编(Guest Associate Editor),主要负责叶绿体基因组结构变异及相关生物信息学工具(Structural Variation of the Chloroplast Genome and Related Bioinformatics Tools)栏目稿件的组稿与评审(https://www.frontiersin.org/research-topics/43287/structuralvariation-of-the-chloroplast-genome-and-related-bioinformatics-tools)。

Extrafloral nectary-the sleeping beauty of plant science

Cotton is one of the most important cash crops,its growth season coincides with a high incidence of diverse groups of pests,leading to heavy use of pesticides.Recent identification of a signaling protein as a candidate regulator of cotton extrafloral nectary provides a new insight into the formation of sophisticated defense mechanisms in plants.

Characteristics of long-distance mobile mRNAs from shoot to root in grafted plant species

Thousands of long-distance mobile mRNAs were identified from different grafting systems,based on high-throughput sequencing technology.Moreover,the long-distance delivery of RNAs was proved to involve multiple mechanisms.Here,we analyzed the homology,motif,and tRNA-like structure(TLS)of long-distance mobile mRNAs identified by RNA-seq as well as the RNA-binding protein(RBP)in nine grafting combinations including Arabidopsis thaliana,Vitis vinifera,Cucumis sativus,Citrullus lanatus,Nicotiana benthamiana,Malus domestica,Pyrus spp.,Glycine max and Phaseolus vulgaris.Although several mRNAs were found to be shared in herbaceous,woody,and related species,the vast majority of long-distance mobile mRNAs were species-specific.Four non-specific movement-related motifs were identified,while the TLS was not necessary for mRNA long distance mobility.In addition,we found that RBPs were conserved among herbaceous and woody plants as well as related species.This paper reports a further in-depth analysis of the endogenous mechanisms by which the species-specific transportable m RNAs were selected by bioinformatics,in order to provide insights for future research on long-distance mobile mRNAs.

SPATULA as a Versatile Tool in Plant:The Progress and Perspectives of SPATULA(SPT)Transcriptional Factor

With the rapid development of modern molecular biology and bioinformatics,many studies have proved that transcription factors play an important role in regulating the growth and development of plants.SPATULA(SPT)belongs to the bHLH transcription family and participates in many processes of regulating plant growth and development.This review systemically summarizes the multiple roles of SPT in plant growth,development,and stress response,including seed germination,flowering,leaf size,carpel development,and root elongation,which is helpful for us to better understand the functions of SPT.

Strategies and prospects for melatonin to alleviate abiotic stress in horticultural plants

Melatonin is a conserved pleiotropic molecule in animals and plants.Melatonin is involved in many development processes and stress responses;thus,exploring its function in plants,particularly in horticultural plants,has become a rapidly developing field.Many studies have revealed that phytomelatonin acts as a plant biostimulant and increase its tolerance to various abiotic stressors,including extreme temperature,drought,osmotic disturbance,heavy metals,and ultraviolet(UV).Melatonin appears to have roles in the scavenging of reactive oxygen species(ROS)and other free radicals,affecting the primary and secondary metabolism of plants,regulating the transcripts of stress-related enzymes and transcription factors,and crosstalk with other hormones under different environmental conditions.This pleiotropy makes phytomelatonin an attractive regulator to improve resistance to abiotic stress in plants.The recent discovery of the potential phytomelatonin receptor CAND2/PMTR1 and the proposition of putative models related to the phytomelatonin signaling pathways makes phytomelatonin a new plant hormone.Based on relevant studies from our laboratory,this review summarizes the phytomelatonin biosynthetic and metabolic pathways in plants and the latest research progress on phytomelatonin in abiotic stress of horticultural plants.This study will provide a reference for elucidating the regulatory mechanism of phytomelatonin affecting the resistance to abiotic stress in plants.

Management of Strawberry Grey Mold Disease Using Biocontrol Agents and Plant Extracts

Strawberry (Fragaria × ananassa Duch.) is a significant global soft fruit crop, prized for its nutrient content and pleasant flavor. However, diseases, particularly grey mold caused by Botrytis cinerea Pers. Fr. poses major constraints to strawberry production and productivity. Grey mold severely impacts fruit quality and quantity, diminishing market value. This study evaluated five B. cinerea isolates from various locations in the Ri-Bhoi district of Meghalaya. All isolates were pathogenic, with isolate SGM 2 identified as highly virulent. Host range studies showed the pathogen-producing symptoms in the fava bean pods, marigold, gerbera, and chrysanthemum flowers and in the fava bean, gerbera, and lettuce leaves. In vitro tests revealed that neem extract (15% w/v) achieved the highest mycelial growth inhibition at 76.66%, while black turmeric extract (5% w/v) had the lowest inhibition at 9.62%. Dual culture methods with bio-control agents indicated that Bacillus subtilis recorded the highest mean inhibition at 77.03%, while Pseudomonas fluorescens had the lowest at 20.36% against the two virulent isolates. Pot evaluations demonstrated that B. subtilis resulted in the lowest percent disease index at 20.59%, followed by neem extract at 23.31%, with the highest disease index in the control group at 42.51%. Additionally, B. subtilis significantly improved plant growth, yielding an average of 0.32 kg compared to 0.14 kg in the control. The promising results of B. subtilis and neem leaf extract from this study suggest their potential for eco-friendly managing grey mold in strawberries under field conditions.

Wild soybean(Glycine soja)transcription factor GsWRKY40 plays positive roles in plant salt tolerance

Wild soybean(Glycine soja),a relative of cultivated soybean,shows high adaptability to adverse environmental conditions.We identified and characterized a wild soybean transcription factor gene,GsWRKY40,that promotes plant salt stress.GsWRKY40 was highly expressed in wild soybean roots and was up-regulated by salt treatment.GsWRKY40 was localized in nucleus and demonstrated DNA-binding activities but without transcriptional activation.Mutation and overexpression of GsWRKY40 altered salt tolerance of Arabidopsis plants.To understand the molecular mechanism of GsWRKY40 in regulating plant salt resistance,we screened a cDNA library and identified a GsWRKY40 interacting protein GsbHLH92 by using yeast two-hybrid approach.The physical interaction of GsWRKY40 and GsbHLH92 was confirmed by co-immunoprecipitation(co-IP),GST pull-down,and bimolecular fluorescence complementation(BiFC)techniques.Intriguingly,co-overexpression of GsWRKY40 and GsbHLH92 resulted in higher salt tolerance and lower ROS levels than overexpression of GsWRKY40 or GsbHLH92 in composite soybean plants,suggesting that GsWRKY40 and GsbHLH92 may synergistically regulate plant salt resistance through inhibiting ROS production.qRT-PCR data indicated that the expression level of GmSPOD1 gene encoding peroxidase was cooperatively regulated by GsWRKY40 and GsbHLH92,which was confirmed by using a dual luciferase report system and yeast one-hybrid experiment.Our study reveals a pathway that GsWRKY40 and GsbHLH92 collaboratively up-regulate plant salt resistance through impeding GmSPOD1 expression and reducing ROS levels,providing a novel perspective on the regulatory mechanisms underlying plant tolerance to abiotic stresses.

Statistics as Part of Scientific Reasoning in Plant Sciences:Overlooked Issues and Recommended Solutions

New research tools for modern life sciences are emerging every few years and being implemented to reveal the underlying mechanisms of scientific questions of interest.However,statistical practice in modern life sciences has barely moved forward and probably has regressed.In many cases,the decisions from biological experiments are predominantly made by using significant P values involving inappropriate statistical analyses and standards,and positive,favored results are preferentially reported (Fanelli,2012;Head et al.,2015;Demidenko,2016;Yong, 2017).

Tea plant (Camellia sinensis) lipid metabolism pathway modulated by tea field microbe (Colletotrichum camelliae) to promote disease

Tea is one of the most popular healthy and non-alcoholic beverages worldwide.Tea anthracnose is a disease in tea mature leaves and ultimately affects yield and quality.Colletotrichum camelliae is a dominant fungal pathogen in the tea field that infects tea plants in China.The pathogenic factors of fungus and the susceptible factors in the tea plant are not known.In this work,we performed molecular and genetic studies to observe a cerato-platanin protein CcCp1 from C.camelliae,which played a key role in fungal pathogenicity.CcCp1 mutants lost fungal virulence and reduced the ability to produce conidia.Transcriptome and metabolome were then performed and analysed in tea-susceptible and tea-resistant cultivars,Longjing 43 and Zhongcha 108,upon C.camelliae wild-type CCA andCcCp1 infection,respectively.The differentially expressed genes and the differentially accumulated metabolites in tea plants were clearly overrepresented such as linolenic acid and linoleic acid metabolism,glycerophospholipid metabolism,phenylalanine biosynthesis and metabolism,biosynthesis of f lavonoid,f lavone and f lavonol etc.In particular,the accumulation of jasmonic acid was significantly increased in the susceptible cultivar Longjing 43 upon CCA infection,in the fungal CcCp1 protein dependent manner,suggesting the compound involved in regulating fungal infection.In addition,other metabolites in the glycerophospholipid and phenylalanine pathway were observed in the resistant cultivar Zhongcha 108 upon fungal treatment,suggesting their potential role in defense response.Taken together,this work indicated C.camelliae CcCp1 affected the tea plant lipid metabolism pathway to promote disease while the lost function of CcCp1 mutants altered the fungal virulence and plant response.

Selenium species transforming along soil–plant continuum and their beneficial roles for horticultural crops

Selenium(Se)acquirement from daily diet can help reduce the risk of many diseases.The edible parts of crop plants are the main source of dietary Se,while the Se content in crops is determined by Se bioavailability in soil.We summarize recent research on the biogeochemical cycle of Se driven by specific microorganisms and emphasize the oxidizing process in the Se cycle.Moreover,we discuss how plant root exudates and rhizosphere microorganisms affect soil Se availability.Finally,we cover beneficial microorganisms,including endophytes,that promote crop quality and improve crop tolerance to environmental stresses.Se availability to plants depends on the balance between adsorption and desorption,reduction,methylation and oxidation,which are determined by interactions among soil properties,microbial communities and plants.Reduction and methylation processes governed by bacteria or fungi lead to declined Se availability,while Se oxidation regulated by Se-oxidizing microorganisms increases Se availability to plants.Despite a much lower rate of Se oxidization compared to reduction and methylation,the potential roles of microbial communities in increasing Se bioavailability are probably largely underestimated.Enhancing Se oxidation and Se desorption are crucial for the promotion of Se bioavailability and uptake,particularly in Se-deficient soils.Beneficial roles of Se are reported in terms of improved crop growth and quality,and enhanced protection against fungal diseases and abiotic stress through improved photosynthetic traits,increased sugar and amino acid contents,and promoted defense systems.Understanding Se transformation along the plant-soil continuum is crucial for agricultural production and even for human health.

The Function of GABA in Plant Cell Growth, Development and Stress Response

Gamma-aminobutyric acid(GABA)is a ubiquitous four-carbon non-protein amino acid that is involved in various physiological processes of plant growth and development,such as root architecture,stem elongation,leaf senescence,pollen tube growth,fruit ripening,and seed germination.GABA is also related to plant stress responses,such as drought,salt,cold,and heat stresses.Regulation of GABA in plant stress responses is complex and involves multiple signaling pathways,including calcium and hormone signaling.This paper systematically reviews the synthesis,metabolic pathways and regulatory role of GABA in plants,which will provide new insights into the understanding of plant growth and stress responses and offer novel strategies for improving crop productivity and stress.

Cassava Me RS40 is required for the regulation of plant salt tolerance

Soil salinity affects the expression of serine/arginine-rich(SR) genes and isoforms by alternative splicing, which in turn regulates the adaptation of plants to stress.We previously identified the cassava spliceosomal component 35 like(SCL) and SR subfamilies, belonging to the SR protein family, which are extensively involved in responses to abiotic stresses.However, the post-transcriptional regulatory mechanism of cassava arginine/serine-rich(RS) subfamily in response to salt stress remains to be explored.In the current study, we identified 37 genes of the RS subfamily from 11 plant species and systematically investigated the transcript levels of the RS40 and RS31 genes under diverse abiotic stress conditions.Subsequently, an analysis of the conserved protein domains revealed that plant RS subfamily genes were likely to preserve their conserved molecular functions and played critical functional roles in responses to abiotic stresses.Importantly, we found that overexpression of MeRS40 in Arabidopsis enhanced salt tolerance by maintaining reactive oxygen species homeostasis and up-regulating the salt-responsive genes.However,overexpression of MeRS40 gene in cassava reduced salt tolerance due to the depression of its endogenous gene expression by negative autoregulation of its own pre-mRNA.Moreover, the MeRS40 protein interacted with MeU1-70Ks(MeU1-70Ka and MeU1-70Kb) in vivo and in vitro, respectively.Therefore, our findings highlight the critical role of cassava SR proteins in responses to salt stress in plants.

Unveiling plant defense arsenal: metabolic strategies in Brassica oleracea during black rot disease

Alterations in plant metabolism play a key role in the complex plant-pathogen interactions.However,there is still a lack of knowledge about the connection between changes in primary and specialized metabolism and the plant defense against diseases that impact crops.Thus,we aim to study the metabolic reprograming in Brassica oleracea plants upon infection by Xanthomonas campestris pv.campestris(Xcc).To accomplish this,we utilized a combination of untargeted and targeted metabolomics,through UPLC-Q-TOF-MS/MS and 1H-NMR,in two crop lines differing in resistance thatwere evaluated at two-and four-week intervals following inoculation(T1 and T2,respectively).Besides,to depict the physiological status of the plant during infection,enzymatic activities related to the carbohydrate pathway and oxidative stress were studied.Our results revealed different temporal dynamics in the responses of the susceptible vs.resistant crops lines.Resistant B.oleracea line suppresses carbohydrate metabolism contributing to limit nutrient supplies to the bacterium and prioritizes the induction of defensive compounds such as indolic glucosinolates,salicylic acid,phenylpropanoids and phytoalexins precursors at early infection stages.In contrast,the susceptible line invests in carbohydratemetabolism,including enzymatic activities related to the hexoses turnover,and activates defense signaling related to reactive oxygen species.Thus,each line triggers a different metabolic strategy that will affect how the plant overcomes the disease in terms of resistance and growth.This work provides first insights of a fine-tuned metabolic regulation during Xcc infection in B.oleracea that will contribute to develop new strategies for plant disease management.

Inventory and Management of Fungi Associated with Banana Plant through the Use of Allium ampeloprasum and Cymbopogon citratus Extracts

Despite the nutritional, economic and medicinal values of banana plant, independent of the region and production system is confronted with some diseases such as the fungi disease. These fungal diseases are responsible for the low yields. The objective of this study was to improve the sanitary state of banana plant. To achieve this objective, fungi associated with banana leaves were isolated on Potato Dextrose Agar (PDA) culture medium and their identification was done on the basis of morphological and microscopic characteristics using reference documents. Antifungal activity of Allium ampeloprasum and Cymbopogon citratus extracts were evaluated in vitro on agar medium on the development of Pseudocercospora fijiensis, P. musicola and Pestalopsis sp. The results showed that banana plant harbours a diversity of fungal species, the most frequent being P. fijiensis (51.58%), Pestalopsis sp. (15.47%) and P. musicola (12.03%). Aqueous extracts of C. citratus at the concentration of 15 mg/ml, inhibited 100% of the radial growth of P. fijiensis and Pestalopsis sp with a fungitoxic activity. Similarly, ethanolic extract A. ampeloprasum inhibited at 100% the radial growth of Pestalopsis sp. This antifungal activity was fungistatic. These results suggest that the aqueous and ethanol extracts of the tested plants could be used as alternatives to chemical products in the fight against banana diseases especially Sigatoka. Hence further studies need to be undertaken to isolate the active compounds from these extracts with fungicidal potential.

A Novel Mechanism Underlying the Coordination of Plant Growth and Salt Stress Response

Salt stress is a major environmental stress that threats crop growth and yield.It is of great significance to study the molecular genetic network of plants in response to salt stress and to cultivate salt-tolerant crop varieties for national food security.A study published in Nature Plants,Dr.ZHAO Chunzhao’s group from the CAS Center for Excellence in Molecular Plant Sciences(CEMPS),Chinese Academy of Science,uncovers a novel mechanism underlying the coordination of plant growth and salt tolerance in plants.

Toxic and Antifeedant Effects of Different Pesticidal Plant Extracts against Beet Armyworm (Spodoptera exigua)

The beet armyworm(BAW),Spodoptera exigua(Lepidoptera:Noctuidae)is a highly destructive pest of vegetables and field crops.Management of beet armyworm primarily relies on synthetic pesticides,which is threatening the beneficial community and environment.Most importantly,the BAW developed resistance to synthetic pesticides with making it difficult to manage.Therefore,alternative and environment-friendly pest management tactics are urgently required.The use of pesticidal plant extracts provides an effective way for a sustainable pest management program.To evaluate the use of pesticidal plant extracts against BAW,we selected six plant species(Lantana camara,Aloe vera,Azadirachta indica,Cymbopogon citratus,Nicotiana tabacum,and Ocimum basilicum)for initial screening experiment.Four out of six plant species such as A.indica,N.tabacum,C.citratus and O.basilicum showed promising mortality of more than 50%.Therefore,we selected these four plant extracts for the subsequent experiments.Through contact bioassay,A.indica showed high mortality 66.63%,followed by the N.tabacum 53.33%,at 10%w/v concentration.Similarly,N.tabacum showed the highest mortality rate,66%at 10%w/v concentration,followed by the A.indica 46%through feeding bioassay.Furthermore,the feeding deterrence assay showed that C.citratus had a high antifeedant index(−50)followed by A.indica(−39),and N.tabacum(−28).In living plant assay,the N.tabacum extract showed a low mean damage score 3.6 on living cotton plant followed by C.citratus 4.5 and A.indica 5.5.Hence,extracts of three plant species provided promising results against the BAW,which can minimize the use of synthetic chemicals,particularly for small landholding farmers.Further studies are also required to evaluate the effects of these plant extract against BAW on cotton plants under field conditions to optimize the further use.

Ca^(2+)-homeostasis Differs Between Plant Species with Different Cold-tolerance at 4 ℃ Chilling

A comparative study was carried out on the EM_cytochemical localization of calcium and Ca 2+ _ATPase activity in the suspension_cultured cells between the chilling_sensitive maize ( Zea mays L. cv. Black Mexican Sweet) and chilling_insensitive Trititrigia ( Triticum sect. Trititrigia mackey) at 4 ℃ chilling. When maize and Tyititrigia cells were cultured at 26 ℃, electron microscopic observations revealed that the electron_dense calcium antimonate deposits, an indication of the calcium localization, were localized mainly in the vacuoles, and few was found in the cytosol and nuclei. The electron_dense cerium phosphate deposits, an indication of Ca 2+ _ATPase activity, were abundantly distributed on the plasma membrane (PM). When the cells from both species were cultured at 4 ℃ for 1 and 3 h, an elevation of Ca 2+ level in the cytosol and nuclei was observed, whereas the cerium phosphate deposits on the PM showed no quantitative difference from those of the 26 ℃_cultured cells, indicating that the enzymatic activities were not altered during these chilling periods. However, there was a distinct difference in the dynamics of the Ca 2+ distribution and the PM Ca 2+ _ATPase activity between maize and Trititrigia when chilled at 4 ℃ for 12, 24 and 72 h. In maize cells, a large number of Ca 2+ deposits still existed in the cytosol and nuclei, and the PM Ca 2+ _ATPase became less and less active, and even inactive at all. In Trititrigia cells, the increased cytosolic and nuclear Ca 2+ ions decreased after 12 h chilling. By chilling up to 24 and 72 h, the intracellular Ca 2+ concentration had been restored to a similar low level as those of the warm temperature_cultured cells, while the activity of the PM Ca 2+ _ATPase maintained high. The transient cytosolic and nuclear Ca 2+ increase and the activities of PM Ca 2+ _ATPase during chilling are discussed in relation to plant cold hardiness.

Conservation genomic investigation of an endangered conifer,Thuja sutchuenensis,reveals low genetic diversity but also low genetic load

Endangered species generally have small populations with low genetic diversity and a high genetic load.Thuja sutchuenensis is an endangered conifer endemic to southwestern China.It was once considered extinct in the wild,but in 1999 was rediscovered.However,little is known about its genetic load.We collected 67 individuals from five wild,isolated T.sutchuenensis populations,and used 636,151 SNPs to analyze the level of genetic diversity and genetic load in T.sutchuenensis to delineate the conservation units of T.sutchuenensis,based on whole transcriptome sequencing data,as well as target capture sequencing data.We found that populations of T.sutchuenensis could be divided into three groups.These groups had low levels genetic diversity and were moderately genetically differentiated.Our findings also indicate that T.sutchuenensis suffered two severe bottlenecks around the Last Glaciation Period and Last Glacial Maximum.Among Thuja species,T.sutchuenensis presented the lowest genetic load and hence might have purged deleterious mutations efficiently through purifying selection.However,distribution of fitness effects analysis indicated a high extinction risk for T.sutchuenensis.Multiple lines of evidence identified three management units for T.sutchuenensis.Although T.sutchuenensis possesses a low genetic load,low genetic diversity,suboptimal fitness,and anthropogenic pressures all present an extinction risk for this rare conifer.This might also hold true for many endangered plant species in the mountains all over the world.

A phenology-based vegetation index for improving ratoon rice mapping using harmonized Landsat and Sentinel-2 data

Ratoon rice,which refers to a second harvest of rice obtained from the regenerated tillers originating from the stubble of the first harvested crop,plays an important role in both food security and agroecology while requiring minimal agricultural inputs.However,accurately identifying ratoon rice crops is challenging due to the similarity of its spectral features with other rice cropping systems(e.g.,double rice).Moreover,images with a high spatiotemporal resolution are essential since ratoon rice is generally cultivated in fragmented croplands within regions that frequently exhibit cloudy and rainy weather.In this study,taking Qichun County in Hubei Province,China as an example,we developed a new phenology-based ratoon rice vegetation index(PRVI)for the purpose of ratoon rice mapping at a 30 m spatial resolution using a robust time series generated from Harmonized Landsat and Sentinel-2(HLS)images.The PRVI that incorporated the red,near-infrared,and shortwave infrared 1 bands was developed based on the analysis of spectro-phenological separability and feature selection.Based on actual field samples,the performance of the PRVI for ratoon rice mapping was carefully evaluated by comparing it to several vegetation indices,including normalized difference vegetation index(NDVI),enhanced vegetation index(EVI)and land surface water index(LSWI).The results suggested that the PRVI could sufficiently capture the specific characteristics of ratoon rice,leading to a favorable separability between ratoon rice and other land cover types.Furthermore,the PRVI showed the best performance for identifying ratoon rice in the phenological phases characterized by grain filling and harvesting to tillering of the ratoon crop(GHS-TS2),indicating that only several images are required to obtain an accurate ratoon rice map.Finally,the PRVI performed better than NDVI,EVI,LSWI and their combination at the GHS-TS2 stages,with producer's accuracy and user's accuracy of 92.22 and 89.30%,respectively.These results demonstrate that the proposed PRVI based on HLS data can effectively identify ratoon rice in fragmented croplands at crucial phenological stages,which is promising for identifying the earliest timing of ratoon rice planting and can provide a fundamental dataset for crop management activities.

Morpho-cultural, Pathogenicity and Molecular Characterization of Phyllosticta capitalensis Inciting Cavendish Banana Freckle Disease in Hainan

[Objectives]The study was to identify the casual agent of freckle disease on Cavendish banana in Hainan Province,China.[Methods]Fungal isolates were isolated from affected leaf tissues and identified by the morphological features,molecular identification and pathogenicity test.[Results]The fungus isolated from affected leaf tissues was identified as Phyllosticta capitalensis based on the morphological properties of the colony and spore,coupled with sequence analyses of the internal transcribed spacer(ITS)region and the large subunit(LSU)rDNA gene.Koch s postulates were fulfilled by successfully re-isolating the pathogen from the artificial inoculated leaves.[Conclusions]P.capitalensis is a new pathogen responsible for Cavendish banana freckle disease in Hainan.