MdWRKY40is directly promotes anthocyanin accumulation and blocks MdMYB15L, the repressor of MdCBF2, which improves cold tolerance in apple

Cold stress is an important factor that limits apple production. In this study, we examined the tissue-cultured plantlets of apple rootstocks ‘M9T337' and ‘60-160', which are resistant and sensitive to cold stress, respectively. The enriched pathways of differentially expressed genes(DEGs) and physiological changes in ‘M9T337' and ‘60-160' plantlets were clearly different after cold stress(1°C) treatment for 48 h, suggesting that they have differential responses to cold stress. The differential expression of WRKY transcription factors in the two plantlets showed that MdWRKY40is and MdWRKY48 are potential regulators of cold tolerance. When we overexpressed MdWRKY40is and MdWRKY48in apple calli, the overexpression of MdWRKY48 had no significant effect on the callus, while MdWRKY40is overexpression promoted anthocyanin accumulation, increased callus cold tolerance, and promoted the expression of anthocyanin structural gene MdDFR and cold-signaling core gene MdCBF2. Yeast one-hybrid screening and electrophoretic mobility shift assays showed that MdWRKY40is could only bind to the MdDFR promoter. Yeast twohybrid screening and bimolecular fluorescence complementation showed that MdWRKY40is interacts with the CBF2inhibitor MdMYB15L through the leucine zipper(LZ). When the LZ of MdWRMY40is was knocked out, MdWRKY40is overexpression in the callus did not affect MdCBF2 expression or callus cold tolerance, indicating that MdWRKY40is acts in the cold signaling pathway by interacting with MdMYB15L. In summary, MdWRKY40is can directly bind to the MdDFR promoter in order to promote anthocyanin accumulation, and it can also interact with MdMYB15L to interfere with its inhibitory effect on MdCBF2, indirectly promoting MdCBF2 expression, and thereby improving cold tolerance.These results provide a new perspective for the cold-resistance mechanism of apple rootstocks and a molecular basis for the screening of cold-resistant rootstocks.

MIR1868 negatively regulates rice cold tolerance at both the seedling and booting stages

Low temperature causes rice yield losses of up to 30%–40%,therefore increasing its cold tolerance is a breeding target.Few genes in rice are reported to confer cold tolerance at both the vegetative and reproductive stages.This study revealed a rice-specific 24-nt miRNA,miR1868,whose accumulation was suppressed by cold stress.Knockdown of MIR1868 increased seedling survival,pollen fertility,seed setting,and grain yield under cold stress,whereas its overexpression conferred the opposite phenotype.Knockdown of MIR1868 increased reactive oxygen species(ROS)scavenging and soluble sugar content under cold stress by increasing the expression of peroxidase genes and sugar metabolism genes,and its overexpression produced the opposite effect.Thus,MIR1868 negatively regulated rice cold tolerance via ROS scavenging and sugar accumulation.

Vegetation C–N–P accumulation and allocation patterns at the community level in early restored plantations in the loess hilly-gully region

Accumulation of vegetation biomass is a crucial process for carbon fixation in the early stage of afforestation and a primary driving force for subsequent ecological functions.Accurately assessing the storage and allocation of elements in plantations is essential for their management and estimating carbon sink capacity.However,current knowledge of the storage and allocation patterns of elements within plant organs at the community level is limited.To clarify the distribution patterns of elements in plant organs at the community level,we measured the biomass within plant organs of five typical plantations in the early stage of afforestation in the loess hilly-gully region.We assessed the main drivers of element accumulation and distribution by employing redundancy analysis and random forest.Results revealed significant differences in biomass storages among plantations and a significant effect of plantation type on the storages of elements within plant organs.Furthermore,the dominant factors influencing C–N–P storage and allocation at the community level were found to be inconsistent.While the storage of elements was mainly influenced by stand openness,total soil nitrogen,and plant diversity,the allocation of elements in organs was mainly influenced by stand openness and soil water content.Overall,the spatial structure of the community had an important influence on both element storage and allocation,but soil conditions played a more important role in element allocation than in storage.Random forest results showed that at the community level,factors influencing element storage and allocation within plant organs often differed.The regulation of elemental storage could be regulated by the major growth demand resources,while the allocation was regulated by other limiting class factors,which often differed from those that had a significant effect on element storage.The differences in plant organ elemental storage and allocation drivers at the community level reflect community adaptation strategies and the regulation of resources by ecosystems in combination with plants.Our study provides valuable insights for enhancing plantation C sink estimates and serves as a reference for regulating element storage and allocation at the local scale.

Advances in Cold Tolerance Genes and Their Application in Genetic Engineering of Plant for Cold Tolerance

Low temperature is one of the main environmental stress factors influenc- ing plant growth and development and crop yield. Cold tolerance genes and progress of their application in genetic engineering of plant for cold tolerance were reviewed comprehensively and systematically from the aspect of genes that are in- volved in biosynthesis of osmotic substances, genes coding fatty acid desaturation enzymes, antifreeze protein genes, genes coding antioxidant enzymes and so on, aiming at laying the foundation for genetic improvement of cold tolerance and breeding of plants.

Physiological Mechanism for Anthocyanins to Strengthen the Drought Tolerance of Plants

This paper summarized the possible physiological mechanism by which anthocyanins strengthen the tolerance of plants to drought. Drought stress can in-duce plant cel s to synthesize and accumulate anthocyanins. The photochemical properties, subcel ular accumulation sites and spatial distributions in plant organs and tissues of anthocyanins determine their function of strengthening plant tolerance, which is realized by three possible physiological mechanisms： （1） anthocyanins and their chelated metal ions can optimize the osmoregulation ability of the plant cel s by directly acting as the osmoregulation substances of the cel s, （2） anthocyanins with suitable spatial locations can reduce the photoinhibition of the plants under drought stresses, （3） anthocyanins can effectively maintain and improve the active oxygen-scavenging capacity of the plant cel s under drought conditions. Therein, that the anthocyanins enhance the antioxidant capacity of the plant cel s under drought stresses is probably the main reason for the anthocyanins to strengthen the drought tolerance of plants. This review could provide a reference for the mechanism re-search of the drought resistance and the breeding of the drought-resistant cultivars for the plants holding the ability to synthesize and accumulate anthocyanins.

Priming for Saline-Alkaline Tolerance in Rice:Current Knowledge and Future Challenges

Soil salinization and/or alkalization is a major constraint to crop production worldwide.Approximately 60% of the cultivated land is affected by salt,over half of which is alkalized.Alkaline soils are characterized by high alkalinity and typically high salinity,which creates a complex saline-alkaline(SA) stress that affects plant growth.Rice cultivation has been accepted as an important strategy for effective utilization of SA land if water is available for irrigation.Nevertheless,as a salt-sensitive plant,rice plants suffer severe SA-induced damage,which results in poor plant growth and grain yield.Various approaches have been employed to improve rice productivity in SA land.Among them,the priming technique has emerged as a powerful method for enhancing SA tolerance in rice plants.In this review,we summarized how SA stress damages rice plants,and then presented how priming treatment can mitigate such damage.

Twin model-based fault detection and tolerance approach for in-core self-powered neutron detectors

The in-core self-powered neutron detector(SPND)acts as a key measuring device for the monitoring of parameters and evaluation of the operating conditions of nuclear reactors.Prompt detection and tolerance of faulty SPNDs are indispensable for reliable reactor management.To completely extract the correlated state information of SPNDs,we constructed a twin model based on a generalized regression neural network(GRNN)that represents the common relationships among overall signals.Faulty SPNDs were determined because of the functional concordance of the twin model and real monitoring sys-tems,which calculated the error probability distribution between the model outputs and real values.Fault detection follows a tolerance phase to reinforce the stability of the twin model in the case of massive failures.A weighted K-nearest neighbor model was employed to reasonably reconstruct the values of the faulty signals and guarantee data purity.The experimental evaluation of the proposed method showed promising results,with excellent output consistency and high detection accuracy for both single-and multiple-point faulty SPNDs.For unexpected excessive failures,the proposed tolerance approach can efficiently repair fault behaviors and enhance the prediction performance of the twin model.

Plant salt tolerance and Na^+ sensing and transport

Salinity is a global challenge to agricultural production. Understanding Na^+ sensing and transport in plants under salt stress will be of benefit for breeding robustly salt-tolerant crop species. In this review, first, possible salt stress sensor candidates and the root meristem zone as a tissue harboring salt stress-sensing components are proposed. Then,the importance of Na^+ exclusion and vacuolar Na^+ sequestration in plant overall salt tolerance is highlighted. Other Na^+ regulation processes, including xylem Na^+ loading and unloading, phloem Na^+ recirculation, and Na^+ secretion, are discussed and summarized.Along with a summary of Na^+ transporters and channels, the molecular regulation of Na^+ transporters and channels in response to salt stress is discussed. Finally, some largely neglected issues in plant salt stress tolerance, including Na^+ concentration in cytosol and the role of Na^+ as a nutrient, are reviewed and discussed.

Advanced Backcross QTL Analysis for the Whole Plant Growth Duration Salt Tolerance in Rice(Oryza sativa L.)

Salinity is a major factor limiting rice yield in coastal areas of Asia. To facilitate breeding salt tolerant rice varieties, the wholeplant growth duration salt tolerance（ST） was genetically dissected by phenotyping two sets of BC2F5 introgression lines（ILs） for four yield traits under severe natural salt stress and non-stress filed conditions using SSR markers and the methods of advanced backcross QTL（AB-QTL） analysis and selective introgression. Many QTLs affecting four yield traits under salt stress and nonstress conditions were identified, most（〉90%） of which were clustered in 13 genomic regions of the rice genome and involved in complex epistasis. Most QTLs affecting yield traits were differentially expressed under salt stress and non-stress conditions. Our results suggested that genetics complementarily provides an adequate explanation for the hidden genetic diversity for ST observed in both IL populations. Some promising Huanghuazhan（HHZ） ILs with favorable donor alleles at multiple QTLs and significantly improved yield traits under salt stress and non-stress conditions were identified, providing excellent materials and relevant genetic information for improving rice ST by marker-assisted selection（MAS） or genome selection.

Accumulation and distribution of arsenic and cadmium by tea plants

It is important to research the rules about accumulation and distribution of arsenic and cadmium by tea plants,which will give us some scientific ideas about how to control the contents of arsenic and cadmium in tea.In this study,by field investigation and pot trial,we found that mobility of arsenic and cadmium in tea plants was low.Most arsenic and cadmium absorbed were fixed in feeding roots and only small amount was transported to the above-ground parts.Distribution of arsenic and cadmium,based on their concentrations of unit dry matter,in tea plants grown on un-contaminated soil was in the order:feeding roots>stems≈main roots>old leaves>young leaves.When tea plants were grown on polluted soils simulated by adding salts of these two metals,feeding roots possibly acted as a buffer and defense,and arsenic and cadmium were transported less to the aboveground parts.The concentration of cadmium in soil significantly and negatively correlated with chlorophyll content,photosynthetic rate,transpiration rate and biomass production of tea plants.

Roles of MicroRNAs in Plant Stress Tolerance

MicroRNAs （miRNAs） are one kind of small RNA in all eukaryote. MicroRNAs can regulate gene expression of eukaryote; they widely participate in every physiological process. They can block mRNA expression or cleave mRNA by complement to target mRNA. Scholars estimate miRNA genes occuping about 1% of genome, but they can regulate 10%-30% genes of whole genome. The genes are regulated by miRNA including signal proteins, enzymes, transcription factors, and so on. In the field of plant research, the start of miRNA research is later, but it is proved that plant miRNAs are important to every plant physiological process. Now miRNA has become the hotspot of plant molecular biology research. This paper introduced the biology function, action mechanism, researching method and recently development of microRNAs, also focused on advances in plant microRNAs. This paper has important reference value for plant stress tolerance miRNA research.

Genotypic Divergence, Photosynthetic Efficiency, Sodium Extrusion, and Osmoprotectant Regulation Conferred Salt Tolerance in Sorghum

Salt stress is one of the major limitations to modern agriculture that negatively influences plant growth and productivity.Salt tolerant cultivar can provide excellent solution to enhance stress tolerance with plantfitness to unfavorable environments.Therefore,this study was aimed to screen salt tolerant sorghum genotypes through evaluating of different morphological,biochemical,and physiological attributes in response to salinity stress.In this study,we have been evaluated total six sorghum genotypes including Hybrid sorgo,Debgiri,BD-703,BD-706,BD-707,and BD-725 under salt stress(12 dS m^(-1) NaCl).The response variables included length and weight of root and shoot,root:shoot ratio(RSR),photosynthesis(A),transpiration rate(E),elemental concen-trations(K^(+),Na^(+) and K^(+)/Na^(+)),photochemical efficiency of photosystem II(F_(v)/F_(m)),water use efficiency(WUE)and pigment content(chlorophyll a,and b).The results revealed that saline environment significantly reduced all response variables under study of sorghum genotypes,however,Hybrid sorgo remained unmatched by recording the maximum root and shoot traits.The same genotype recorded higher photosynthetic efficiency which was attributed to Na^(+) extrusion,K^(+) uptake and higher K^(+)/Na^(+) ratio(1.8 at stress),while these mechanisms were not fully active in rest of genotypes.Moreover,this study also implies the involvement of proline in imparting tolerance against saline environment in Hybrid sorgo genotype.Overall,BD-703 remained the most salt sensitive genotype as evident from the minimum morphological growth traits and the least biosynthesis of osmoprotectants.Thesefindings open new research avenues for salt stress alleviation by identifying elite salt-to-lerant genotypes of sorghum for breeding programs.

Accumulation Laws of Nitrogen and Phosphorus in Wetland Plants

To study the accumulation regularity of nitrogen and phosphorus in typical constructive plants in coastal wetland,samples of Suaeda glauca(Bunge) Bunge,Phragmites austrahs and Tamarix chinensis Lour,were taken from the Yellow River Delta National Coast Wetland Nature Reserve,nitrogen and phosphorus content in plants was measured and analyzed.The results showed that ① nitrogen and phosphorus content in different wetland plants is correlated;② different species in the same place and the same species in different spaces show different accumulation regularity of nitrogen and phosphorus;③ nitrogen and phosphorus content in plants is closely related to nitrogen and phosphorus content in the habitat;④ nitrogen content in T.chinensis Lour,is the highest,the mean is 11.63 g/kg,and phosphorus content in S glauca(Bunge) Bunge is the highest,the mean is 1.38 g/kg;⑤ nitrogen content in the 3 species:T.chinensis Lour.> S.glauca(Bunge) Bunge > P.australis;⑥ nitrogen content in aboveground parts of all plants is significantly higher than that in underground parts,and phosphorus content in aboveground parts of all plants except S.glauca(Bunge) Bunge is significantly higher than that in underground parts;⑦ nitrogen content in the 3 species in the study area is significantly higher than phosphorus content in these species.

The Comparison of Cold tolerance of Three Species of Evergreen Broad-leaved Woody Plants

[Objectives]This study aimed to select evergreen broad-leaved woody plants with higher ornamental value and stronger cold tolerance for introduction from the south to the north,and to apply them to urban greening,so as to enrich the plant community structure of the landscape in the northern region.[Methods]Three species of evergreen broad-leaved woody plants,i.e.,Ligustrum lucidum,Ilex cornuta and Eriobotrya japonica,were selected as the experimental materials.The morphological performances and the changes of the physiological indexes were observed and measured during the overwintering period in the open field in Beijing.The relationship between the indexes and the low temperature was also analyzed.The strength of cold tolerance of the three species was compared.[Results]The electrical conductivity,the contents of MDA and proline were negatively correlated with the corresponding low temperature.The contents of soluble sugar and soluble protein increased with the dropping temperature,but they had little response to the short-term temperature rise.[Conclusions]Combined with morphological and physiological indexes,it was found that the changes of the contents of proline and soluble sugar among the physiological indexes were closely related to the cold tolerances of the three tree species of broad-leaved woody plants.The cold tolerance of I.cornuta was the strongest,E.japonica was the second,and that of L.lucidum was the worst.

Accumulation of cadmium and copper by female Oxya chinensis (Orthopera: Acridoidea) in soil-plant-insect system

One purpose of this research is to present accumulation of cadmium （Cd） and copper （Cu） by female Oxya chinensis （Orthopera： Acridoidea） in a simulated soil-plant-insect ecosystem treated with Cd. Fourth-instar nymphs of O. chinensis had been fed on wheat （Triticurn aestivum） seedlings contaminated with Cd and Cu for one month. In the ecosystem, the Cd concentration in wheat seedlings rose greatly with the increasing of Cd in the soil, but the Cu concentration in wheat seedlings was not found elevated. There was a highly significant difference（P〈0.05） in Cd concentrations of wheat seedlings and not any significant difference（P〉0.05） in Cu concentrations of wheat seedlings. The Cd and Cu concentration in different body part-head, thorax, abdomen, and hind femur, varied under different Cd concentrations in soil. There were significant differences （P〈0.05） in the four parts of Cd and Cu accumulations with all treatments. The order of Cd accumulation was thorax 〉abdomen 〉head 〉hind femur and the Cu was abdomen 〉thorax 〉 head〉hind femur. The results indicated that Cd and Cu were accumulated from the soil to grasshoppers through the plant; that is to say, Cd and Cu in environment could be transported to animal or human via food chain.

Phenotypic, Stress Tolerance and Plant Growth Promoting Characteristics of Rhizobial Isolates from Selected Wild Legumes of Semiarid Region, Tirupati, India

Rhizobia are vital for nitrogen input, fertility of soil and legume plant growth. Knowledge on rhizobial diversity from arid and semiarid areas is important for dry land agriculture in the context of climatic change and for economic utilization. This study provides morphological, biochemical, stress tolerance and plant growth promoting characteristics of fifteen rhizobial isolates from the nodules of same number of wild legumes and one isolate from cultivated Arachis hypogea from semi-arid region, Tirupati. The bacterial isolates were confirmed as rhizobia based on colony morphology and biochemical tests. Based on the colour change of YMA-BTB medium, eight isolates were identified as slow growers and six were fast growers. The isolates differed in growth pattern, colony morphology, antibiotic resistance at higher concentrations and uniformity in utilization of carbon and nitrogen sources. The isolates are tolerant to NaCl up to one percent, displayed normal growth at temperatures 28℃ - 30℃, at neutral pH and poor growth at pH 5and 9. The isolates varied in the production of EPS and IAA, positive for phosphate solubilization and siderophore formation. This functional diversity displayed by the isolates can be utilised for the legume crop production by cross inoculation.

Research Progress on Plant Anti-Freeze Proteins

Plant antifreeze proteins(AFPs)are special proteins that can protect plant cells from ice crystal damage in low-temperature environments,and they play a crucial role in the process of plants adapting to cold environ-ments.Proteins with these characteristics have been found infish living in cold regions,as well as many plants and insects.Although research on plant AFPs started relatively late,their application prospects are broad,leading to the attention of many researchers to the isolation,cloning,and genetic improvement of plant AFP genes.Studies have found that the distribution of AFPs in different species seems to be the result of independent evolu-tionary events.Unlike the AFPs found infish and insects,plant AFPs have multiple hydrophilic ice-binding domains,and their recrystallization inhibition activity is about 10–100 times that offish and insect AFPs.Although different plant AFPs have the characteristics of low TH and high RI,their DNA and amino acid sequences are completely different,with small homology.With in-depth research and analysis of the character-istics and mechanisms of plant AFPs,not only has our understanding of plant antifreeze mechanisms been enriched,but it can also be used to improve crop varieties and enhance their freezing tolerance,yield,and quality through genetic engineering.In addition,the study of plant AFPs also contributes to our understanding of freezing resistance mechanisms in other organisms and provides new research directions for thefield of biotech-nology.Therefore,based on the analysis of relevant literature,this article will delve into the concepts,character-istics,research methods,and mechanisms of plant AFPs,summarize the latest research progress and application prospects of AFPs in plant,and provide prospects for the future development of AFP gene research.

Effects of Intercropping with CaryophyllaceaeAccumulator Plants on Cadmium Accumulation ofCyphomandra betacea Seedlings

The pot experiments were conducted to study the effects of intercropping with Pseudostellaria maximowicziana,Malachiumaquaticum and Stellaria media on Cd accumulation of Cyphomandra betacea seedlings.Compared with the monoculture,intercropping with Caryophyllaceae endarachneyllaceae accumulator plants decreased the biomass of C.betacea seedlings,and also reduced the photosynthetic pigment contents in C.betacea seedlings,which involve chlorophyll a,chlorophyll b,total chlorophyll and carotenoid.Intercropping with P.maximowicziana and M.aquaticum increased the Cd contents in shoots of C.betacea seedlings,which increased by 65.02%and 25.61%,respectively,compared with the monoculture.Intercropping with S.media reduced the Cd contents in shoots of C.betacea seedlings,which were reduced by 4.68%compared with the monoculture.When intercropping with C.betacea seedlings,the Cd accumulation amounts of 3 Caryophyllaceae accumulator plants were ranked as S.media>P.maximowicziana>M.aquaticum.Intercropping with S.media could effectively reduce Cd accumulation of C.betacea seedlings under Cd-contaminated soil condition.

Free proline accumulation in rice plants under different leaf water potential

Seedlings of drought-tolerance rice varieties Han 501and Han A03,and the drought sensitive varietiesNanjing 11 and Yanjing 2 were raised in a paddyfield and transplanted into pots at the age of 8leaves.Water stress started at the tillering stage byholding water from 0 MPa of the soil water potentialin pots till the leaves showed seriously wilting.

Nutrient Accumulation Characteristics of Facility Soils with Different Planting Years in Lateritic Red Soil Region of Guangxi

[Objectives]To explore the nutrient accumulation characteristics of facility soil in different planting years in the lateritic red soil region of Guangxi.[Methods]The soil samples of facility cultivation and open field cultivation were collected in the lateritic red soil region of Guangxi,and the changes of soil pH,water-soluble salts,organic matter,available nutrients and total nutrients were analyzed.[Results]The acidification of the facility soil in the lateritic red soil region of Guangxi became more obvious with the extension of greenhouse planting years,the soil pH decreased by 0.34 units after continuous planting for 10 years,and the water-soluble content was more than 3 times that of the open field and it increased with the extension of the planting years.In addition,the degree of secondary salinization in facility soil became more serious,mainly moderate and mild salinization.The contents of soil organic matter,alkali-hydrolyzed nitrogen,available phosphorus,available potassium,total nitrogen and total phosphorus in the facility soil increased significantly,while total potassium did not change significantly.[Conclusions]This study is expected to provide a scientific basis for facility soil fertilization management,and to promote the sustainable and healthy development of facility cultivation industry.