Dossa Komivi, Diouf Diaga, Cissé Ndiaga
Centre d'Etudes Régional pour l'Amélioration de l'Adaptation à la SécheresseSénégal; Laboratoire Campus de Biotechnologies Végétales, Département de Biologie Végétale, Faculté des Sciences et Techniques, Université Cheikh Anta DiopDakar, Sénégal.
Laboratoire Campus de Biotechnologies Végétales, Département de Biologie Végétale, Faculté des Sciences et Techniques, Université Cheikh Anta Diop Dakar, Sénégal.
Front Plant Sci. 2016 Oct 13;7:1522. doi: 10.3389/fpls.2016.01522. eCollection 2016.
Sesame is a survivor crop cultivated for ages in arid areas under high temperatures and limited water conditions. Since its entire genome has been sequenced, revealing evolution, and functional characterization of its abiotic stress genes became a hot topic. In this study, we performed a whole-genome identification and analysis of Hsf gene family in sesame. Thirty genes encoding Hsf domain were found and classified into 3 major classes A, B, and C. The class A members were the most representative one and Hsf genes were distributed in 12 of the 16 linkage groups (except the LG 8, 9, 13, and 16). Evolutionary analysis revealed that, segmental duplication events which occurred around 67 MYA, were the primary force underlying Hsf genes expansion in sesame. Comparative analysis also suggested that sesame has retained most of its Hsf genes while its relatives viz. tomato and potato underwent extensive gene losses during evolution. Continuous purifying selection has played a key role in the maintenance of Hsf genes in sesame. Expression analysis of the Hsf genes in sesame revealed their putative involvement in multiple tissue-/developmental stages. Time-course expression profiling of Hsf genes in response to drought stress showed that 90% Hsfs are drought responsive. We infer that classes B-Hsfs might be the primary regulators of drought response in sesame by cooperating with some class A genes. This is the first insight into this gene family and the results provide some gene resources for future gene cloning and functional studies toward the improvement in stress tolerance of sesame.
芝麻是一种历经岁月在高温和水分有限的干旱地区种植的抗逆作物。由于其全基因组已被测序，揭示其非生物胁迫基因的进化和功能特性成为一个热门话题。在本研究中，我们对芝麻中的热激转录因子（Hsf）基因家族进行了全基因组鉴定和分析。发现了30个编码Hsf结构域的基因，并将其分为A、B、C三大类。A类成员最具代表性，Hsf基因分布在16个连锁群中的12个（除LG 8、9、13和16外）。进化分析表明，大约在6700万年前发生的片段重复事件是芝麻中Hsf基因扩张的主要驱动力。比较分析还表明，芝麻保留了其大部分Hsf基因，而其近缘物种番茄和马铃薯在进化过程中经历了广泛的基因丢失。持续的纯化选择在芝麻Hsf基因的维持中起了关键作用。芝麻中Hsf基因的表达分析表明它们可能参与多个组织/发育阶段。Hsf基因对干旱胁迫的时间进程表达谱显示，90%的Hsf对干旱有响应。我们推断B类Hsf可能通过与一些A类基因合作成为芝麻干旱响应的主要调节因子。这是对该基因家族的首次深入研究，研究结果为未来芝麻抗逆性改良的基因克隆和功能研究提供了一些基因资源。
