Table_3_GhGLK1 a Key Candidate Gene From GARP Family Enhances Cold and Drought Stress Tolerance in Cotton.XLS

Drought and low-temperature stresses are the most prominent abiotic stresses affecting cotton. Wild cotton being exposed to harsh environments has more potential to cope with both biotic and abiotic stresses. Exploiting wild cotton material to induce resistant germplasm would be of greater interest. The candidate gene was identified in the BC2F2 population among Gossypium tomentosum and Gossypium hirsutum as wild male donor parent noted for its drought tolerance and the recurrent parent and a high yielding but drought susceptible species by genotyping by sequencing (GBS) mapping. Golden2-like (GLK) gene, which belongs to the GARP family, is a kind of plant-specific transcription factor (TF) that was silenced by virus-induced gene silencing (VIGS). Silencing of GhGLK1 in cotton results in more damage to plants under drought and cold stress as compared with wild type (WT). The overexpression of GhGLK1 in Arabidopsis thaliana showed that the overexpressing plants showed more adaptability than the WT after drought and cold treatments. The results of trypan blue and 3,3′-diaminobenzidine (DAB) staining showed that after drought and cold treatment, the leaf damage in GhGLK1 overexpressed plants was less as compared with the WT, and the ion permeability was also lower. This study suggested that the GhGLK1 gene may be involved in the regulation of drought and cold stress response in cotton. Our current research findings add significantly to the existing knowledge of cold and drought stress tolerance in cotton.

干旱与低温胁迫是影响棉花的最主要非生物胁迫 (abiotic stresses)。野生棉花长期暴露于严苛环境中，其应对生物胁迫 (biotic stresses) 与非生物胁迫的潜力更强。利用野生棉花材料培育抗逆种质资源 (resistant germplasm) 具有重要研究价值。研究人员以耐旱的野生雄性供体亲本毛棉 (Gossypium tomentosum) 与高产但易感干旱的陆地棉 (Gossypium hirsutum) 作为轮回亲本，通过测序分型 (genotyping by sequencing，GBS) 定位，在其BC2F2群体中鉴定到候选基因。属于GARP家族的Golden2-like (GLK) 基因是一类植物特异性转录因子 (transcription factor，TF)，本研究通过病毒诱导基因沉默 (virus-induced gene silencing，VIGS) 对其进行沉默操作。在棉花中沉默GhGLK1后，相较于野生型 (wild type，WT) 植株，其在干旱与低温胁迫下受到的损伤更为严重。将GhGLK1在拟南芥 (Arabidopsis thaliana) 中过表达后发现，经干旱与低温处理后的过表达植株相较于野生型具有更强的适应性。台盼蓝 (trypan blue) 与3,3′-二氨基联苯胺 (3,3′-diaminobenzidine，DAB) 染色结果显示，经干旱与低温处理后，GhGLK1过表达植株的叶片损伤程度低于野生型，且离子渗透率也更低。本研究表明GhGLK1基因可能参与调控棉花对干旱与低温胁迫的响应。当前的研究发现显著丰富了现有关于棉花低温与干旱胁迫耐受性的认知。