Gautam Tinku, Saripalli Gautam, Gahlaut Vijay, Kumar Anuj, Sharma P K, Balyan H S, Gupta P K
Department of Genetics and Plant Breeding, Ch. Charan Singh University, Meerut, 250004, India.
Department of Plant Molecular Biology, University of Delhi South Campus, New Delhi, 110021, India.
Mol Biol Rep. 2019 Apr;46(2):2327-2353. doi: 10.1007/s11033-019-04691-0. Epub 2019 Mar 4.
SWEET proteins represent one of the largest sugar transporter family in the plant kingdom and play crucial roles in plant development and stress responses. In the present study, a total of 108 TaSWEET genes distributed on all the 21 wheat chromosomes were identified using the latest whole genome sequence (as against 59 genes reported in an earlier report). These 108 genes included 14 of the 17 types reported in Arabidopsis and also included three novel types. Tandem duplications (22) and segmental duplications (5) played a significant role in the expansion of TaSWEET family. A number of cis-elements were also identified in the promoter regions of TaSWEET genes, indicating response of TaSWEET genes during development and also during biotic/abiotic stresses. The TaSWEET proteins carried 4-7 trans-membrane helices (TMHs) showing diversity in structure. Phylogenetic analysis using SWEET proteins of wheat and 8 other species gave four well-known clusters. Expression analysis involving both in silico and in planta indicated relatively higher expression of TaSWEET genes in water/heat sensitive and leaf rust resistant genotypes. The results provided insights into the functional role of TaSWEETs in biotic and abiotic stresses, which may further help in planning strategies to develop high yielding wheat varieties tolerant to environmental stresses.
SWEET蛋白是植物界最大的糖转运蛋白家族之一，在植物发育和胁迫反应中发挥着关键作用。在本研究中，利用最新的全基因组序列鉴定出总共108个分布在小麦所有21条染色体上的TaSWEET基因（相比早期报道的59个基因）。这108个基因包括拟南芥中报道的17种类型中的14种，还包括三种新类型。串联重复（22个）和片段重复（5个）在TaSWEET家族的扩张中起了重要作用。在TaSWEET基因的启动子区域也鉴定出了许多顺式作用元件，表明TaSWEET基因在发育过程以及生物/非生物胁迫过程中的响应。TaSWEET蛋白含有4-7个跨膜螺旋（TMH），结构具有多样性。利用小麦和其他8个物种的SWEET蛋白进行系统发育分析得到了四个著名的聚类。涉及电子表达分析和植物体内表达分析表明，TaSWEET基因在对水/热敏感和抗叶锈病的基因型中表达相对较高。这些结果为TaSWEETs在生物和非生物胁迫中的功能作用提供了见解，这可能进一步有助于制定培育耐环境胁迫高产小麦品种的策略。
