Table_1_Structural and functional characteristics and expression profile of the 20S proteasome gene family in Sorghum under abiotic stress.xlsx

The 26S proteasome is a molecular machine that catalyzes and degrades protein intracellularly with the help of its core complex called 20S proteasome. The 20S proteasomes degrade and cleave denatured, cytotoxic, damaged, and unwanted proteins via proteolysis and impart biotic and abiotic stress tolerance in model plants. This study identified 20 genes, namely, 10 SbPA and 10 SbPB that encode for α- and β-subunits of the 20S proteasome in Sorghum bicolor (L.) Moench (2n= 20). These genes have been found distributed on the 1st, 2nd, 3rd, 4th, 5th, 7th, and 10th chromosomes. These sorghum genes were orthologous to corresponding rice. Phylogenetic analysis clustered these genes into seven clades, each with one of the seven α-subunits (1 to 7) and one of the seven β-subunits (1 to 7). In silico gene expression analysis suggested that nine genes were involved in abiotic stress response (cold, drought, and abscisic acid hormone). The expression of these proteasomal genes was studied in shoots and roots exposed to different abiotic stresses (cold, drought, and abscisic acid) by quantitative real-time polymerase chain reaction. A significant increase in the relative fold expression of SbPBA1, SbPAA1, SbPBG1, SbPBE1, and SbPAG1 genes under ABA and drought stress provides an insight into its involvement in abiotic stress. No expression was observed for cold stress of these genes indicating their non-involvement. It is believed that additional investigation into the SbPA/SbPB genes would aid in the creation of S. bicolor cultivars that are resistant to climate change.

26S蛋白酶复合体作为一种分子机械，在20S蛋白酶核心复合体的辅助下，催化并降解细胞内的蛋白质。20S蛋白酶通过蛋白质水解作用降解和切割变性的、细胞毒性的、受损的和不需要的蛋白质，为模式植物提供生物和非生物胁迫耐受性。本研究鉴定出20个基因，即10个SbPA和10个SbPB基因，它们编码了高粱（Sorghum bicolor (L.) Moench，2n=20）20S蛋白酶的α和β亚基。这些基因分布在第1、2、3、4、5、7和10号染色体上。这些高粱基因与相应的水稻基因同源。系统发育分析将这些基因聚类成七个分支，每个分支包含七个α亚基（1至7）和七个β亚基（1至7）之一。通过计算机模拟基因表达分析，推测有九个基因参与非生物胁迫响应（寒冷、干旱和脱落酸激素）。通过定量实时聚合酶链反应（qRT-PCR）研究了在暴露于不同非生物胁迫（寒冷、干旱和脱落酸）的茎和根中这些蛋白酶基因的表达。SbPBA1、SbPAA1、SbPBG1、SbPBE1和SbPAG1基因在ABA和干旱胁迫下相对表达量的显著增加，揭示了其在非生物胁迫中的参与作用。这些基因在寒冷胁迫下没有观察到表达，表明它们不参与其中。人们认为，对SbPA/SbPB基因的进一步研究将有助于培育出对气候变化具有抵抗力的S. bicolor品种。