Multiple Stress Tolerance Research Articles

GASA Proteins: Review of Their Functions in Plant Environmental Stress Tolerance.

Gibberellic acid-stimulated Arabidopsis (GASA) gene family is a class of functional cysteine-rich proteins characterized by an N-terminal signal peptide and a C-terminal-conserved GASA domain with 12 invariant cysteine (Cys) residues. GASA proteins are widely distributed among plant species, and the majority of them are involved in the signal transmission of plant hormones, the regulation of plant development and growth, and the responses to different environmental constraints. To date, their action mechanisms are not completely elucidated. This review reports an overview of the diversity, structure, and subcellular localization of GASA proteins, their involvement in hormone crosstalk and redox regulation during development, and plant responses to abiotic and biotic stresses. Knowledge of this complex regulation can be a contribution to promoting multiple abiotic stress tolerance with potential agricultural applications through the engineering of genes encoding GASA proteins and the production of transgenic plants.

CRISPR-Cas9-based precise engineering of SlHyPRP1 protein towards multi-stress tolerance in tomato.

Recently, CRISPR-Cas9-based genome editing has been widely used for plant breeding. In our previous report, a tomato gene encoding hybrid proline-rich protein 1 (HyPRP1), a negative regulator of salt stress responses, has been edited using a CRISPR-Cas9 multiplexing approach that resulted in precise eliminations of its functional domains, proline-rich domain (PRD) and eight cysteine-motif (8CM). We subsequently demonstrated that eliminating the PRD domain of HyPRP1 in tomatoes conferred the highest level of salinity tolerance. In this study, we characterized the edited lines under several abiotic and biotic stresses to examine the possibility of multiple stress tolerance. Our data reveal that the 8CM removal variants of HK and the KO alleles of both HK and 15T01 cultivars exhibited moderate heat stress tolerance. Similarly, plants carrying either the domains of the PRD removal variant (PR1v1) or 8CM removal variants (PR2v2 and PR2v3) showed better germination under osmosis stress (up to 200 mM mannitol) compared to the WT control. Moreover, the PR1v1 line continuously grew after 5 days of water cutoff. When the edited lines were challenged with pathogenic bacteria of Pseudomonas syringae pv. tomato (Pto) DC3000, the growth of the bacterium was significantly reduced by 2.0- to 2.5-fold compared to that in WT plants. However, the edited alleles enhanced susceptibility against Fusarium oxysporum f. sp. lycopersici, which causes fusarium wilt. CRISPR-Cas9-based precise domain editing of the SlHyPRP1 gene generated multi-stress-tolerant alleles that could be used as genetic materials for tomato breeding.

Ectopic expression of DnaJ type-I protein homolog of Vigna aconitifolia (VaDJI) confers ABA insensitivity and multiple stress tolerance in transgenic tobacco plants.

Reduced crop productivity results from altered plant physiological processes caused by dysfunctional proteins due to environmental stressors. In this study, a novel DnaJ Type-I encoding gene, VaDJI having a zinc finger motif in its C-terminal domain was found to be induced early upon treatment with heat stress (within 5min) in a heat tolerant genotype of Vigna aconitifolia RMO-40. VaDJI is induced by multiple stresses. In tobacco, ectopic expression of VaDJI reduced ABA sensitivity during seed germination and the early stages of seedling growth of transgenic tobacco plants. Concomitantly, it also improved the ability of transgenic tobacco plants to withstand drought stress by modulating the photosynthetic efficiency, with the transgenic plants having higher Fv/Fm ratios and reduced growth inhibition. Additionally, transgenic plants showed a reduced build-up of H2O2 and lower MDA levels and higher chlorophyll content during drought stress, which attenuated cell damage and reduced oxidative damage. An analysis using the qRT-PCR study demonstrated that VaDJI overexpression is associated with the expression of some ROS-detoxification-related genes and stress-marker genes that are often induced during drought stress responses. These findings suggest a hypothesis whereby VaDJI positively influences drought stress tolerance and ABA signalling in transgenic tobacco, and suggests that it is a potential gene for genetic improvement of drought and heat stress tolerance in crop plants.

Improvement of stress multi-tolerance and bioethanol production by Saccharomyces cerevisiae immobilised on biochar: Monitoring transcription from defence-related genes

The study determined the protective role of using biochar as immobilisation carrier against multiple stresses encountered by Saccharomyces cerevisiae assessing transcription from important metabolic routes involved in the molecular mechanisms triggered during inhibitory bioprocess conditions. Immobilised cells exhibited higher bioethanol titre (39 g L−1) and productivity (7.72 g L−1 h−1) at elevated temperatures compared with the suspended culture that yielded 34 g L−1 and 1.99 g L−1 h−1 respectively. Fermentation at 39 °C resulted in 2.15-fold increase of HSP104 relative mRNA expression in suspended cells, while the gene was induced by 0.5-fold using the immobilised biocatalyst. A similar response occurred for HSF1 and TPS exhibiting 3.0- and 3.8-fold increase using suspended cells as opposed to the application of immobilised cells where transcription of the aforementioned genes was raised by 0.0- and 2.6-fold upon temperature increase respectively. Transcription from MSN2/MSN4 under the aforementioned conditions indicated the protective role of cell attachment on the biomaterial against stimulation of the heat shock response route and oxidative stress. Although fermentations conducted under ethanol stress resulted in failure of the conventional process, immobilised cells produced 21 g L−1 bioethanol exhibiting 7 g L−1 h−1 productivity, while monitoring transcription of HSP12 and HSP104 demonstrated the beneficial use of the proposed technology. Proline accumulation during osmotic stress further supported the elevated bioethanol productivity achieved by the immobilised system, which was 74% higher as opposed to the conventional process. The study confirmed that S. cerevisiae immobilisation on biochar conferred cells with heat tolerance, ethanol tolerance, osmotolerance and improved fermentation capacity. The technology proposed constitutes a sustainable technological alternative to strain modification improving multiple stress-tolerance in bioethanol fermentations.

CRISPR-Cas Genome Editing in Crops: A Promising Frontier for Climate-Smart Agriculture

This comprehensive review paper explores the transformative role of CRISPR-Cas technology in addressing critical challenges faced by agriculture in the era of climate change. The exploration unfolds across four key headings. Firstly, under "Understanding CRISPR-Cas Technology," the paper provides a foundational understanding of the CRISPR-Cas systems, elucidating their intricate mechanisms of genome editing and tracing their evolutionary trajectory in agricultural research. Moving to "Climate-Responsive Targets in Crop Genomes," the review delves into the identification of genes associated with climate resilience, discussing strategies for precise CRISPR-Cas target selection. Case studies illuminate successful gene editing applications, showcasing the potential of this technology in fortifying crops against diverse climatic stressors. The section on "Challenges and Opportunities in Crop Engineering" critically examines hurdles such as off-target effects and navigates risk assessments. It explores the evolving regulatory frameworks and ethical considerations surrounding CRISPR-Cas, shedding light on the ethical dimensions of its implementation. The discussion extends to the innovative prospect of leveraging CRISPR-Cas for conferring multiple stress tolerance in crops, introducing a paradigm shift towards sustainable agriculture. The final section, "Towards Sustainable Agriculture: Future Prospects and Applications," envisions the future impact of CRISPR-Cas on global food security. It highlights the synergy between CRISPR-Cas and precision breeding, emphasizing the integration with conventional breeding programs. The prospective impacts on global food security and agricultural sustainability are explored, presenting CRISPR-Cas as a pivotal tool in developing resilient and high-yielding crops that can address the challenges of a changing climate. This review paper synthesizes insights from understanding the technology to addressing challenges and unlocking opportunities, envisioning a sustainable future where CRISPR-Cas plays a central role in advancing agriculture towards resilience, precision, and global food security.

Screening and identification of multiple abiotic stress responsive candidate genes based on hybrid-sequencing in Vicia sativa

Common vetch is an important leguminous forage for both livestock fodder and green manure and has a tremendous latent capacity in a sustainable agroecosystem. In the present study, a comprehensive transcriptome analysis of the aboveground leaves and underground roots of common vetch under multiple abiotic stress treatments, including NaCl, drought, cold, and cold drought, was performed using hybrid-sequencing technology, i. e. single-molecule real-time sequencing technology (SMRT) and supplemented by next-generation sequencing (NGS) technology. A total of 485,038 reads of insert (ROIs) with a mean length of 2606 bp and 228,261 full-length nonchimeric (FLNC) reads were generated. After deduplication, 39,709 transcripts were generated. Of these transcripts, we identified 1059 alternative splicing (AS) events, 17,227 simple sequence repeats (SSRs), and 1647 putative transcription factors (TFs). Furthermore, 640 candidates long noncoding RNAs (lncRNAs) and 28,256 complete coding sequences (CDSs) were identified. In gene annotation analyses, a total of 38,826 transcripts (97.78%) were annotated in eight public databases. Finally, seven multiple abiotic stress-responsive candidate genes were obtained through gene expression, annotation information, and protein-protein interaction (PPI) networks. Our research not only enriched the structural information of FL transcripts in common vetch, but also provided useful information for exploring the molecular mechanism of multiple abiotic stress tolerance between aboveground and underground tissues in common vetch and related legumes.

Genome-Wide Identification, Evolutionary and Functional Analyses of WRKY Family Members in Ginkgo biloba.

WRKY transcription factors (TFs) are one of the largest families in plants which play essential roles in plant growth and stress response. Ginkgo biloba is a living fossil that has remained essentially unchanged for more than 200 million years, and now has become widespread worldwide due to the medicinal active ingredients in its leaves. Here, 37 WRKY genes were identified, which were distributed randomly in nine chromosomes of G. biloba. Results of the phylogenetic analysis indicated that the GbWRKY could be divided into three groups. Furthermore, the expression patterns of GbWRKY genes were analyzed. Gene expression profiling and qRT-PCR revealed that different members of GbWRKY have different spatiotemporal expression patterns in different abiotic stresses. Most of the GbWRKY genes can respond to UV-B radiation, drought, high temperature and salt treatment. Meanwhile, all GbWRKY members performed phylogenetic tree analyses with the WRKY proteins of other species which were known to be associated with abiotic stress. The result suggested that GbWRKY may play a crucial role in regulating multiple stress tolerances. Additionally, GbWRKY13 and GbWRKY37 were all located in the nucleus, while GbWRKY15 was located in the nucleus and cytomembrane.

PRpnp, a novel dual activity PNP family protein improves plant vigour and confers multiple stress tolerance in Citrus aurantifolia.

Under field conditions, plants are often simultaneously exposed to several abiotic and biotic stresses resulting in significant reductions in growth and yield; thus, developing a multi-stress tolerant variety is imperative. Previously, we reported the neofunctionalization of a novel PNP family protein, Putranjiva roxburghii purine nucleoside phosphorylase (PRpnp) to trypsin inhibitor to cater to the needs of plant defence. However, to date, no study has revealed the potential role and mechanism of either member of this protein group in plant defence. Here, we overexpressed PRpnp in Citrus aurantifolia which showed nuclear-cytoplasmic localization, where it functions in maintaining the intracellular purine reservoir. Overexpression of PRpnp significantly enhanced tolerance to salt, oxidative stress, alkaline pH, drought and two pests, Papilio demoleus and Scirtothrips citri in transgenic plants. Global gene expression studies revealed that PRpnp overexpression up-regulated differentially expressed genes (DEGs) related to ABA- and JA-biosynthesis and signalling, plant defence, growth and development. LC-MS/MS analysis validated higher endogenous ABA and JA accumulation in transgenic plants. Taken together, our results suggest that PRpnp functions by enhancing the endogenous ABA and JA, which interact synergistically and it also inhibits trypsin proteases in the insect gut. Also, like other purine salvage genes, PRpnp also regulates CK metabolism and increases the levels of CK-free bases in transgenic Mexican lime. We also suggest that PRpnp can be used as a potential candidate to develop new varieties with improved plant vigour and enhanced multiple stress resistance.

Overexpression of a DUF740 family gene (LOC_Os04g59420) imparts enhanced climate resilience through multiple stress tolerance in rice.

Functional characterization of stress-responsive genes through the analysis of transgenic plants is a standard approach to comprehend their role in climate resilience and subsequently exploit them for sustainable crop improvement. In this study, we investigated the function of LOC_Os04g59420, a gene of DUF740 family (OsSRDP-Oryza sativa Stress Responsive DUF740 Protein) from rice, which showed upregulation in response to abiotic stress in the available global expression data, but is yet to be functionally characterized. Transgenic plants of the rice OsSRDP gene, driven by a stress-inducible promoter AtRd29A, were developed in the background of cv. Pusa Sugandh 2 (PS2) and their transgene integration and copy number were confirmed by molecular analysis. The three independent homozygous transgenic plants (AtRd29A::OsSRDP rice transformants) showed better resilience to drought, salinity, and cold stresses, but not heat stress, as compared to the non-transformed PS2, which corresponded with their respective relative transcript abundance for OsSRDP. Transgenic plants maintained higher RWC, photosynthetic pigments, and proline accumulation under drought and salinity stresses. Furthermore, they exhibited less accumulation of reactive oxygen species (ROS) than PS2 under drought stress, as seen from the transcript abundance studies of the ROS genes. Under cold stress, OsSRDP transgenic lines illustrated minimal cell membrane injury compared to PS2. Additionally, the transgenic plants showed resistance to a virulent strain of rice blast fungus, Magnaporthe oryzae (M. oryzae). The promoter analysis of the gene in N22 and PS2 revealed the presence of multiple abiotic and biotic stress-specific motif elements supporting our observation on multiple stress tolerance. Based on bioinformatics studies, we identified four potential candidate interaction partners for LOC_Os04g59420, of which two genes (LOC_Os05g09640 and LOC_Os06g50370) showed co-expression under biotic and drought stress along with OsSRDP. Altogether, our findings established that stress-inducible expression of OsSRDP can significantly enhance tolerance to multiple abiotic stresses and a biotic stress.

Adaptação Laboratorial Evolutiva para obtenção de cepas de bactérias ácido-lácticas de interesse industrial - uma revisão

Abstract The purpose of this review was to describe how adaptive laboratory evolution (ALE) can provide improvement to lactic acid bacteria (LAB) strains for their application in industrial biotechnological processes. This review was carried out according to the Preferred Reporting Items for Systematic Review and Meta-analysis (PRISMA) approach, incorporating the ScienceDirect and Scopus databases. The literature search yielded 4,167 (ScienceDirect) and 27 (Scopus) articles, which were reduced to 12 after applying the inclusion /exclusion criteria. The studies revolved around LAB of the genera Lactobacillus, Lactococcus, Leuconostoc and Enterococcus and the application of ALE experiments in batch mode, fed-batch mode, or both, and aimed to produce strains with increased lactic acid production capabilities, higher cell viability, and multiple-stress tolerance. The studies demonstrated that ALE is an efficient approach for strain modification towards desired phenotypic functions and does not require genetic engineering. Knowledge of the cellular and molecular responses of microorganisms to stress enables an understanding of the adaptation mechanisms of LAB strains for survival and increased production of metabolites throughout ALE experiments.

Genotypic diversity and abiotic stress response profiling of short-grain aromatic landraces of rice (Oryza sativa L. Indica)

This study evaluated the physiological responses and genetic diversity of selected short-grain aromatic rice landraces of Northern Eastern Ghats of India to multiple abiotic stresses. Results revealed that drought, salt and flooding stress remarkably declined plant biomass, relative growth index (RGI), relative water content (RWC), leaf photosynthesis, PSII activity, SPAD relative index, and elevated effect was found in susceptible IR64 (susceptible check) variety. We employed molecular marker analysis to characterize 21 rice genotypes using 32 SSR primers related to drought, flooding and salinity tolerance QTLs. Our analysis suggests significantly high polymorphism (93.12%) in 96 loci. The mean value of polymorphism information content (PIC), marker index (MI) and resolving power (RP) and heterozygosity index (HI) were 0.326, 1.037, 1.558 and 0.420 respectively. The Jaccard’s similarity coefficient ranged from 0.158 to 0.846 with a mean genetic dissimilarity of 0.647. According to neighbor-joining method of clustering, all genotypes were grouped into two major and five sub-clusters which is concurrent with a very broad genetic base (K = 5) obtained with STRUCTURE analysis. Taken together, six aromatic genotypes Basubhoga, Dudhamani, Kalajeera, Laktimachi, Kuyerkuling and Tulasi are genetically very close to drought-tolerant (N22) and flooding tolerant (FR13A) cultivar whereas, salt-tolerant (Pokkali) very close to Sapuri and Muktabali. The degree of genetic variants obtained from this profiling could be useful for landrace conservation, selection and global implications for multiple abiotic stress tolerance.

A systematical genome-wide analysis and screening of WRKY transcription factor family engaged in abiotic stress response in sweetpotato

BackgroundWRKY transcription factors play pivotal roles in regulating plant multiple abiotic stress tolerance, however, a genome-wide systematical analysis of WRKY genes in sweetpotato is still missing.ResultsHerein, 84 putative IbWRKYs with WRKY element sequence variants were identified in sweetpotato reference genomes. Fragment duplications, rather than tandem duplications, were shown to play prominent roles in IbWRKY gene expansion. The collinearity analysis between IbWRKYs and the related orthologs from other plants further depicted evolutionary insights into IbWRKYs. Phylogenetic relationships displayed that IbWRKYs were divided into three main groups (I, II and III), with the support of the characteristics of exon-intron structures and conserved protein motifs. The IbWRKY genes, mainly from the group Ib, displayed remarkable and diverse expression profiles under multiple abiotic stress (NaCl, PEG6000, cold and heat) and hormone (ABA, ACC, JA and SA) treatments, which were determined by RNA-seq and qRT-PCR assays, suggesting their potential roles in mediating particular stress responses. Moreover, IbWRKY58L could interact with IbWRKY82 as revealed by yeast two-hybrid based on the protein interaction network screening. And abiotic stress-remarkably induced IbWRKY21L and IbWRKY51 were shown to be localized in the nucleus and had no transactivation activities.ConclusionThese results provide valuable insights into sweetpotato IbWRKYs and will lay a foundation for further exploring functions and possible regulatory mechanisms of IbWRKYs in abiotic stress tolerance.

Type 2C Protein Phosphatases MoPtc5 and MoPtc7 Are Crucial for Multiple Stress Tolerance, Conidiogenesis and Pathogenesis of Magnaporthe oryzae.

Protein kinases and phosphatases catalyze the phosphorylation and dephosphorylation of their protein substrates, respectively, and these are important mechanisms in cellular signal transduction. The rice blast fungus Magnaporthe oryzae possesses 6 protein phosphatases of type 2C class, including MoPtc1, 2, 5, 6, 7 and 8. However, only very little is known about the roles of these phosphatases in filamentous fungi. Here in, we deployed genetics and molecular biology techniques to identify, characterize and establish the roles of MoPtc5 and MoPtc7 in M. oryzae development and pathogenicity. We found that during pathogen-host interaction, MoPTC7 is differentially expressed. Double deletion of MoPTC7 and MoPTC5 suppressed the fungal vegetative growth, altered its cell wall integrity and reduced its virulence. The two genes were found indispensable for stress tolerance in the phytopathogen. We also demonstrated that disruption of any of the two genes highly affected appressorium turgor generation and Mps1 and Osm1 phosphorylation levels. Lastly, we demonstrated that both MoPtc5 and MoPtc7 are localized to mitochondria of different cellular compartments in the blast fungus. Taken together, our study revealed synergistic coordination of M. oryzae development and pathogenesis by the type 2C protein phosphatases.

ThASR3 confers salt and osmotic stress tolerances in transgenic Tamarix and Arabidopsis

BackgroundASR (abscisic acid-, stress-, and ripening-induced) gene family plays a crucial role in responding to abiotic stresses in plants. However, the roles of ASR genes protecting plants against high salt and drought stresses remain unknown in Tamarix hispida.ResultsIn this study, a salt and drought-induced ASR gene, ThASR3, was isolated from Tamarix hispida. Transgenic Arabidopsis overexpressing ThASR3 exhibited stimulating root growth and increasing fresh weight compared with wild-type (WT) plants under both salt and water deficit stresses. To further analyze the gain- and loss-of-function of ThASR3, the transgenic T. hispida plants overexpressing or RNA interference (RNAi)-silencing ThASR3 were generated using transient transformation. The overexpression of ThASR3 in Tamarix and Arabidopsis plants displayed enhanced reactive oxygen species (ROS) scavenging capability under high salt and osmotic stress conditions, including increasing the activities of antioxidant enzymes and the contents of proline and betaine, and reducing malondialdehyde (MDA) content and electrolyte leakage rates.ConclusionOur results indicate that ThASR3 functions as a positive regulator in Tamarix responses to salt and osmotic stresses and confers multiple abiotic stress tolerances in transgenic plants, which may have an important application value in the genetic improvement of forest tree resistance.

A Study of Scion Phenotypes in Pummelo Grafted onto a New Citrus Rootstock Citrus junos ‘Pujiang Xiangcheng’

Citrus is one of the most important fruit crops in the world. Citrus junos Siebold ex Tanaka cv. Pujiang Xiangcheng is a new rootstock with a good grafting affinity and multiple abiotic stress tolerance. In this study, the effects of ‘Pujiang Xiangcheng’ and two commonly used rootstocks for Citrus maxima (Burm.) Merrill cv. Guanxi Miyou, considering their growth, photosynthetic performance, phytohormones and fruit quality, were evaluated. There was little difference between three graft combinations in the height and diameter of the scions. However, the rootstock ‘Pujiang Xiangcheng’ can cause an up-regulated photosynthetic capacity. In addition, ‘Guanxi Miyou’ on ‘Pujiang Xiangcheng’ had the highest total sugar (TS) content (129.28 mg·g−1) and the lowest titratable acid (TA) content (0.78 g·100 mL−1) in 2020 and the highest TSS (11.84%) in 2021. There was no significant difference in the TSS-to-acid ratio between the fruit of ‘Guanxi Miyou’ on trifoliate orange (13.41) and ‘Pujiang Xiangcheng’ (15.68), but it was significantly higher than that of ‘Guanxi Miyou’ on sour pummelo (11.61). Moreover, the comprehensive fruit quality of ‘Guanxi Miyou’ on ‘Pujiang Xiangcheng’ was better than on sour pummelo and trifoliate orange based on two-year statistics. We suggest that ‘Pujiang Xiangcheng’ might be the appropriate rootstock of ‘Guanxi Miyou’ in production compared with sour pummelo and trifoliate orange.

Cowpea NAC1/NAC2 transcription factors improve growth and tolerance to drought and heat in transgenic cowpea through combined activation of photosynthetic and antioxidant mechanisms.

NAC (NAM/ATAF1/2/CUC2) transcription factors are central switches of growth and stress responses in plants. However, unpredictable interspecies conservation of function and regulatory targets makes the well-studied NAC orthologs inapt for pulse engineering. The knowledge of suitable NAC candidates in hardy pulses like cowpea (Vigna unguiculata (L.) Walp.) is still in infancy, hence warrants immediate biotechnological intervention. Here, we showed that overexpression of two native NAC genes (VuNAC1 and VuNAC2) promoted germinative, vegetative, and reproductive growth and conferred multiple abiotic stress tolerance in a commercial cowpea variety. The transgenic lines displayed increased leaf area, thicker stem, nodule-rich denser root system, early flowering, higher pod production (∼3.2-fold and ∼2.1-fold), and greater seed weight (10.3% and 6.0%). In contrast, transient suppression of VuNAC1/2 caused severe growth retardation and flower inhibition. The overexpressor lines showed remarkable tolerance to major yield-declining terminal stresses, such as drought, salinity, heat, and cold, and recovered growth and seed production by boosting photosynthetic activity, water use efficiency, membrane integrity, Na+ /K+ homeostasis, and antioxidant activity. The comparative transcriptome study indicated consolidated activation of genes involved in chloroplast development, photosynthetic complexes, cell division and expansion, cell wall biogenesis, nutrient uptake and metabolism, stress response, abscisic acid, and auxin signaling. Unlike their orthologs, VuNAC1/2 direct synergistic transcriptional tuning of stress and developmental signaling to avoid unwanted trade-offs. Their overexpression governs the favorable interplay of photosynthesis and reactive oxygen species regulation to improve stress recovery, nutritional sufficiency, biomass, and production. This unconventional balance of strong stress tolerance and agronomic quality is useful for translational crop research and molecular breeding of pulses.

Overexpression of durum wheat NAC transcription factor TtNTL3A promotes early flowering and increases multiple stress tolerance in transgenic Arabidopsis

Plant-specific NAC transcription factors play important roles in plant development processes, hormone signaling and response to biotic and abiotic stresses. Here, a newly identified membrane-bound NAC gene, designated as TtNTL3A, was isolated from durum wheat. TtNTL3A was homologous to bread wheat TaNAC8 and rice OsNAC8. Moreover, yeast trans-activation assays revealed that TtNTL3A is a transcriptional activator. TtNTL3A was highly expressed in developing seeds and was induced by abiotic stresses, abscisic acid treatment and the infection with Fusarium graminearum. Besides, Transgenic Arabidopsis overexpressing TtNTL3A showed early flowering phenotype and higher tolerance to salt and drought stresses. RT-qPCR analysis revealed that drought and salt-responsive genes were highly expressed in transgenic lines compared to WT plants. Besides, these lines showed resistance to Fusarium graminearum, which was accompanied by a higher expression of pathogenesis-related genes (AtPR-1, Atpdf1.2, and AtNPR1) in TtNTL3A-OE lines. These findings suggest that TtNTL3A is an interesting target of genetic engineering to improve wheat tolerance to biotic and abiotic stresses.

Genome-Wide Characterization of Ascorbate Peroxidase Gene Family in Peanut (Arachis hypogea L.) Revealed Their Crucial Role in Growth and Multiple Stress Tolerance.

Ascorbate peroxidase (APX), an important antioxidant enzyme, plays a significant role in ROS scavenging by catalyzing the decrease of hydrogen peroxide under various environmental stresses. Nevertheless, information about the APX gene family and their evolutionary and functional attributes in peanut (Arachis hypogea L.) was not reported. Therefore, a comprehensive genome-wide study was performed to discover the APX genes in cultivated peanut genome. This study identified 166 AhAPX genes in the peanut genome, classified into 11 main groups. The gene duplication analysis showed that AhAPX genes had experienced segmental duplications and purifying selection pressure. Gene structure and motif investigation indicated that most of the AhAPX genes exhibited a comparatively well-preserved exon-intron pattern and motif configuration contained by the identical group. We discovered five phytohormones-, six abiotic stress-, and five growth and development-related cis-elements in the promoter regions of AhAPX. Fourteen putative ah-miRNAs from 12 families were identified, targeting 33 AhAPX genes. Furthermore, we identified 3,257 transcription factors from 38 families (including AP2, ARF, B3, bHLH, bZIP, ERF, MYB, NAC, WRKY, etc.) in 162 AhAPX genes. Gene ontology and KEGG enrichment analysis confirm the role of AhAPX genes in oxidoreductase activity, catalytic activity, cell junction, cellular response to stimulus and detoxification, biosynthesis of metabolites, and phenylpropanoid metabolism. Based on transcriptome datasets, some genes such as AhAPX4/7/17/77/82/86/130/133 and AhAPX160 showed significantly higher expression in diverse tissues/organs, i.e., flower, leaf, stem, roots, peg, testa, and cotyledon. Likewise, only a few genes, including AhAPX4/17/19/55/59/82/101/102/137 and AhAPX140, were significantly upregulated under abiotic (drought and cold), and phytohormones (ethylene, abscisic acid, paclobutrazol, brassinolide, and salicylic acid) treatments. qRT-PCR-based expression profiling presented the parallel expression trends as generated from transcriptome datasets. Our discoveries gave new visions into the evolution of APX genes and provided a base for further functional examinations of the AhAPX genes in peanut breeding programs.

Consensus genomic regions associated with multiple abiotic stress tolerance in wheat and implications for wheat breeding

In wheat, a meta-analysis was performed using previously identified QTLs associated with drought stress (DS), heat stress (HS), salinity stress (SS), water-logging stress (WS), pre-harvest sprouting (PHS), and aluminium stress (AS) which predicted a total of 134 meta-QTLs (MQTLs) that involved at least 28 consistent and stable MQTLs conferring tolerance to five or all six abiotic stresses under study. Seventy-six MQTLs out of the 132 physically anchored MQTLs were also verified with genome-wide association studies. Around 43% of MQTLs had genetic and physical confidence intervals of less than 1 cM and 5 Mb, respectively. Consequently, 539 genes were identified in some selected MQTLs providing tolerance to 5 or all 6 abiotic stresses. Comparative analysis of genes underlying MQTLs with four RNA-seq based transcriptomic datasets unravelled a total of 189 differentially expressed genes which also included at least 11 most promising candidate genes common among different datasets. The promoter analysis showed that the promoters of these genes include many stress responsiveness cis-regulatory elements, such as ARE, MBS, TC-rich repeats, As-1 element, STRE, LTR, WRE3, and WUN-motif among others. Further, some MQTLs also overlapped with as many as 34 known abiotic stress tolerance genes. In addition, numerous ortho-MQTLs among the wheat, maize, and rice genomes were discovered. These findings could help with fine mapping and gene cloning, as well as marker-assisted breeding for multiple abiotic stress tolerances in wheat.

Analysis of hybrid combining ability for growth and multiple stress tolerance traits in the Pacific white shrimp, Litopenaeus vannamei

To identify optimal mating combinations for Litopenaeus vannamei, a linear mixed model was used to estimate the general combining ability (GCA) and specific combining ability (SCA) for growth and multiple stress tolerance [high salt (35‰), low pH (6 ± 0.1), and high ammonia nitrogen (70 mg/L) co-stress] traits in 47 combinations of L. vannamei. The results showed that the SCA in the parents played a dominant role in the offspring traits. The highest GCAs were observed for females of strain O and males of strain B (0.602 and 8.889, respectively), indicating that the dams of strain O and sires of strain B could be used as maternal and paternal lines to increase multiple stress resistance in the next generation. The growth traits of the hybrid combination strain G♂ × strain H♀ exhibited the highest degree of heterosis (9.838%–46.518%) and a generally high SCA (0.643–8.596) among all mating combinations. The SCA was the highest for the strain N♂ × strain O♀ multiple stress tolerance (30.131), while the heterosis for that combination strain was the third-highest. The combinations of strain G♂ × strain H♀ and strain N♂ × strain O♀ can be used as candidate combinations for rapid growth and multiple stress tolerance, respectively.