Insight into the AP2/ERF transcription factor superfamily in sesame and expression profiling of DREB subfamily under drought stress

Abstract

BackgroundSesame is an important oilseed crop mainly grown in inclement areas with high temperatures and frequent drought. Thus, drought constitutes one of the major constraints of its production. The AP2/ERF is a large family of transcription factors known to play significant roles in various plant processes including biotic and abiotic stress responses. Despite their importance, little is known about sesame AP2/ERF genes. This constitutes a limitation for drought-tolerance candidate genes discovery and breeding for tolerance to water deficit.ResultsOne hundred thirty-two AP2/ERF genes were identified in the sesame genome. Based on the number of domains, conserved motifs, genes structure and phylogenetic analysis including 5 relatives species, they were classified into 24 AP2, 41 DREB, 61 ERF, 4 RAV and 2 Soloist. The number of sesame AP2/ERF genes was relatively few compared to that of other relatives, probably due to gene loss in ERF and DREB subfamilies during evolutionary process. In general, the AP2/ERF genes were expressed differently in different tissues but exhibited the highest expression levels in the root. Mostly all DREB genes were responsive to drought stress. Regulation by drought is not specific to one DREB group but depends on the genes and the group A6 and A1 appeared to be more actively expressed to cope with drought.ConclusionsThis study provides insights into the classification, evolution and basic functional analysis of AP2/ERF genes in sesame which revealed their putative involvement in multiple tissue-/developmental stages. Out of 20 genes which were significantly up- /down-regulated under drought stress, the gene AP2si16 may be considered as potential candidate gene for further functional validation as well for utilization in sesame improvement programs for drought stress tolerance.Electronic supplementary materialThe online version of this article (doi:10.1186/s12870-016-0859-4) contains supplementary material, which is available to authorized users.

Comprehensive Screening of Some West and Central African Sesame Genotypes for Drought Resistance Probing by Agromorphological, Physiological, Biochemical and Seed Quality Traits

“…Previous studies related to drought research in sesame have applied mainly a moderate stress [7,9,10,12,13,[25][26][27], but in fact, in the semi-arid and arid areas where sesame is commonly grown, drought can last several weeks. Hence, in this study, the response of sesame genotypes for long lasting drought stress was emphasized [8,11].…”

Genome-wide analysis of WRKY gene family in the sesame genome and identification of the WRKY genes involved in responses to abiotic stresses

“…Waterlogging and drought are the most serious abiotic stresses for sesame and result in significant losses (20%-50%) in sesame production within China [24,47]. However, few abiotic stress tolerance genes have been identified in sesame.…”

“…Root samples were collected immediately thereafter and frozen in liquid nitrogen prior to analysis [24]. To further investigate genes important for drought resistance, we harvested plants when the soil water content was reached 35% (0 d controls), 15% (3 d), 10% (7 d), 5% (11 d), and 35% (14 d) after REW.…”

“…Sequencing of the entire sesame genome, and annotation of its 24,148 putative genes, provides an opportunity to identify all the sesame WRKY genes [24][25][26]. In this study, 71 WRKY genes were identified from the sesame genome and analyses of their structure, phylogeny, chromosomal distribution and duplication, conserved motifs, and stimulation in response to waterlogging and drought were performed.…”

Enhancing sesame production in West Africa’s Sahel: a comprehensive insight into the cultivation of this untapped crop in Senegal and Mali

“…For instance, sesame's short cycle time is important for avoiding pest attacks, soil moisture depletion and weathering on the open capsules, hence enabling farmers to harvest as soon as possible without incurring significant yield penalty [33,34]. Moreover, improving drought tolerance and thermotolerance in sesame genotypes should be one of the major objectives of sesame breeding programs mainly in drought-prone areas like West Africa's Sahel [10,[35][36][37]. Sesame biotic constraints have been widely neglected in this area, but observations show that, with the increasing of the crop acreage, diseases and pest attacks are becoming very serious.…”