Genome-wide identification and expression analysis of DREB genes in alfalfa (Medicago sativa) in response to cold stress

Abstract

Dehydration-responsive element-binding proteins (DREBs) belong to members of the AP2/ERF transcription factor superfamily, which has been reported to involve various abiotic-stress responses and tolerance in plants. However, research on the DREB -family is still limited in alfalfa ( Medicago sativa L.), a forage legume cultivated worldwide. The recent genome-sequence release of the alfalfa cultivar “XinJiangDaYe” allowed us to identify 172 DREBs by a multi-step homolog search. The phylogenetic analysis indicated that such MsDREB s could be classified into 5 groups, namely A-1 (56 members), A-2 (39), A-3 (3), A-4 (61) and 13 (A-5 (13), thus adding substantial new members to the DREB -family in alfalfa. Furthermore, a comprehensive survey in silico of conserved motif, gene structure, molecular weight, and isoelectric point (pI) as well as gene expression was conducted. The resulting data showed that, for cold-stress response, 33 differentially expressed MsDREB s were identified with a threshold of Log2-fold > 1, and most of which were transcriptionally upregulated within 48 h during a cold treatment(s). Moreover, the expression profiling of MsDREB s from two ecotypes of alfalfa subspecies i.e. M. sativa ssp. falcata (F56, from a colder region of Central Asia) and M. sativa ssp. sativa (B47, from Near East) revealed that most of the cold-stress responsive MsDREBs exhibited a significantly lower expression in F56, leading to a proposal of the existence of a distinct mechanism(s) for cold tolerance regulated by DREB-related action, which would have been evolved in alfalfa with a genotypic specificity. Additionally, by examining the transcriptome of a freezing-tolerance species ( M. sativa cv. Zhaodong), eight DREBs were found to be implicated in a long-term freezing-stress adaptation with a great potential. Taken together, the current genome-wide identification in alfalfa points to the importance of some MsDREB s in the cold-stress response, providing some promising molecular targets to be functionally characterized for the improvement of cold tolerance in crops including alfalfa.

Tolerant mechanism of model legume plant Medicago truncatula to drought, salt, and cold stresses

“…Recently, the expression profiles of DREBs in M. truncatula and M. sativa are identified in the cold-stress response ( Shu et al, 2016 ; Sheng et al, 2022 ). A cluster of DREB subfamily members on M. truncatula chromosome 6 is induced by both cold and freezing stress ( Shu et al, 2016 ), and 33 MsDREBs are significantly upregulated by cold treatment ( Sheng et al, 2022 ). The genome-wide identification of DREBs in Medicago species provides promising molecular targets for the improvement of cold tolerance in crops.…”

Screening Spring Wheat Genotypes for TaDreb-B1 and Fehw3 Genes under Severe Drought Stress at the Germination Stage Using KASP Technology

“…Moreover, Fructan 1-exohydrolase w3 (Fehw3) gene contribute to the high levels of stem water-soluble carbohydrate remobilization under terminal drought stress [4]. Several authors have reported that TaDreb-B1 and Fehw3 genes are involved in abiotic stress tolerance parameters in several crops [8,[16][17][18]. Chen et al [19] reported that wheat accessions, carrying TaDreb-B1 haplotypes1 and 3, showed drought tolerance.…”

Genome-Wide Identification and Expression Analysis of HSF Transcription Factors in Alfalfa (Medicago sativa) under Abiotic Stress

“…In response to external stimuli, plants’ bodies produce signals that trigger the phosphorylation of downstream proteins, which in turn trigger a number of transcription factors [ 5 ]. Ultimately, plant-associated resistance genes and associated defense systems are induced, thus altering the ability of the plant to adapt to its environment [ 6 , 7 , 8 ].…”