Background: Crop productivity is challenged by abiotic stresses, among which drought stress is the most common.NF-Ygenes, especiallyNF-YAgenes, regulate tolerance to abiotic stress.Results: Soybean NF-Y geneGmNFYA5was identified to have the highest transcript level among all 21NF-YAgenes in soybean (Glycine maxL.) under drought stress. Drought-induced transcript ofGmNFYA5was suppressed by the ABA synthesis inhibitor naproxen (NAP).GmNFYA5transcript was detected in various tissues at vegetative and reproductive growth stages with higher levels in roots and leaves than in other tissues, which was consist with theGmNFYA5promoter: GUS fusion assay. Overexpression ofGmNFYA5in transgenic Arabidopsis plants caused enhanced drought tolerance in seedlings by decreasing stomatal aperture and water loss from leaves. Overexpression and suppression ofGmNFYA5in soybean resulted in increased and decreased drought tolerance, respectively, relative to plants with an empty vector (EV). Transcript levels of ABA-dependent genes (ABI2,ABI3,NCED3,LEA3,RD29A,P5CS1,GmWRKY46,GmNCED2andGmbZIP1) and ABA-independent genes (DREB1A,DREB2A,DREB2B,GmDREB1,GmDREB2andGmDREB3) in transgenic plants overexpressingGmNFYA5were higher than those of wild-type plants under drought stress; suppression ofGmNFYA5transcript produced opposite results. GmNFYA5 probably regulated the transcript abundance ofGmDREB2andGmbZIP1by binding to the promoters in vivo.Conclusions: Our results suggested that overexpression ofGmNFYA5improved drought tolerance in soybean via both ABA-dependent and ABA-independent pathways.

Plants have a series of response mechanisms to adapt when they are subjected to external stress. Calcium-dependent protein kinases (CDPKs) in plants function against a variety of abiotic stresses. We screened 17 CDPKs from drought- and salt-induced soybean transcriptome sequences. The phylogenetic tree divided CDPKs of rice, Arabidopsis and soybean into five groups (I–V). Cis-acting element analysis showed that the 17 CDPKs contained some elements associated with drought and salt stresses. Quantitative real-time PCR (qRT-PCR) analysis indicated that the 17 CDPKs were responsive after different degrees of induction under drought and salt stresses. GmCDPK3 was selected as a further research target due to its high relative expression. The subcellular localization experiment showed that GmCDPK3 was located on the membrane of Arabidopsis mesophyll protoplasts. Overexpression of GmCDPK3 improved drought and salt resistance in Arabidopsis. In the soybean hairy roots experiment, the leaves of GmCDPK3 hairy roots with RNA interference (GmCDPK3-RNAi) soybean lines were more wilted than those of GmCDPK3 overexpression (GmCDPK3-OE) soybean lines after drought and salt stresses. The trypan blue staining experiment further confirmed that cell membrane damage of GmCDPK3-RNAi soybean leaves was more severe than in GmCDPK3-OE soybean lines. In addition, proline (Pro) and chlorophyll contents were increased and malondialdehyde (MDA) content was decreased in GmCDPK3-OE soybean lines. On the contrary, GmCDPK3-RNAi soybean lines had decreased Pro and chlorophyll content and increased MDA. The results indicate that GmCDPK3 is essential in resisting drought and salt stresses.

Potassium (K) is essential to plant growth and development. Foxtail millet (Setaria italic L.) is an important fodder grain crop in arid and semi-arid regions of Asia and Africa because of its strong tolerance to drought and barren stresses. The molecular mechanisms of physiological and biochemical responses and regulations to various abiotic stresses such as low potassium conditions in foxtail millet are not fully understood, which hinders the research and exploitation of this valuable resource. In this research, we demonstrated that the millet variety Longgu 25 was the most insensitive variety to low potassium stress among other five varieties. The transcriptome analysis of Longgu 25 variety revealed a total of 26,192 and 26,849 genes from the K+-deficient and normal transcriptomic libraries by RNA-seq, respectively. A total of 1982 differentially expressed genes (DEGs) were identified including 866 up-regulated genes and 1116 down-regulated genes. We conducted a comparative analysis of these DEGs under low-K+ stress conditions and discovered 248 common DEGs for potassium deprivation among foxtail millet, rice and Arabidopsis. Further Gene Ontology (GO) enrichment analysis identified a series of candidate genes that may involve in K+-deficient response and in intersection of molecular functions among foxtail millet, rice and Arabidopsis. The expression profiles of randomly selected 18 candidate genes were confirmed as true DEGs with RT-qPCR. Furthermore, one of the 18 DEGs, SiMYB3, is specifically expressed only in the millet under low-K+ stress conditions. Overexpression of SiMYB3 promoted the main root elongation and improved K+ deficiency tolerance in transgenic Arabidopsis plants. The fresh weight of the transgenic plants was higher, the primary root length was longer and the root surface-area was larger than those of control plants after K+ deficiency treatments. This study provides a global view of transcriptomic resources relevant to the K+-deficient tolerance in foxtail millet, and shows that SiMYB3 is a valuable genetic resource for the improvement of K+ deficiency tolerance in foxtail millet.

Grain yield (GY) and grain protein content (GPC) are important traits for wheat breeding and production; however, they are usually negatively correlated. The Q gene is the most important domestication gene in cultivated wheat because it influences many traits, including GY and GPC. Allelic variations in the Q gene may positively affect both GY and GPC. Accordingly, we characterized two new Q alleles (Q^s1 and Q^c1-N8) obtained through ethyl methanesulfonate-induced mutagenesis. Compared with the wild-type Q allele, Q^s1 contains a missense mutation in the sequence encoding the first AP₂ domain, whereas Q^c1-N8 has two missense mutations: one in the sequence encoding the second AP₂ domain and the other in the microRNA172-binding site. The Q^s1 allele did not significantly affect GPC or other processing quality parameters, but it adversely affected GY by decreasing the thousand kernel weight and grain number per spike. In contrast, Q^c1-N8 positively affected GPC and GY by increasing the thousand kernel weight and grain number per spike. Thus, we generated novel germplasm relevant for wheat breeding. A specific molecular marker was developed to facilitate the use of the Q^c1-N8 allele in breeding. Furthermore, our findings provide useful new information for enhancing cereal crops via non-transgenic approaches.

Wheat Avenin-like proteins (TaALP) are atypical storage proteins belonging to the Prolamin superfamily. Previous studies on ALPs have focused on the proteins’ positive effects on dough strength, whilst no correlation has been made between TaALPs and the plant immune system. Here, we performed genome-wide characterization of ALP encoding genes in bread wheat. In silico analyses indicated the presence of critical peptides in TaALPs that are active in the plant immune system. Pathogenesis-related nucleotide motifs were also identified in the putative promoter regions of TaALP encoding genes. RT-PCR was performed on TaALP and previously characterised pathogenesis resistance genes in developing wheat caryopses under control and Fusarium graminearum infection conditions. The results showed that TaALP and NMT genes were upregulated upon F. graminearum inoculation. mRNA insitu hybridization showed that TaALP genes were expressed in the embryo, aleurone and sub-aleurone layer cells. Seven TaALP genes were cloned for the expression of recombinant proteins in Escherichia coli , which displayed significant inhibitory function on F. graminearum under anti-fungal tests. In addition, FHB index association analyses showed that allelic variations of two ALP genes on chromosome 7A were significantly correlated with FHB symptoms. Over-expression of an ALP gene on chromosome 7A showed an enhanced resistance to FHB. Yeast two Hybridization results revealed that ALPs have potential proteases inhibiting effect on metacaspases and beta-glucosidases. A vital infection process related pathogen protein, F. graminearum Beta-glucosidase was found to interact with ALPs. Our study is the first to report a class of wheat storage protein or gluten protein with biochemical functions. Due to its abundance in the grain and the important multi-functions, the results obtained in the current study are expected to have a significant impact on wheat research and industry.