Heterogeneous expression of Osa-MIR156bc increases abiotic stress resistance and forage quality of alfalfa
Heterogeneous expression of Osa-MIR156bc increases abiotic stress resistance and forage quality of alfalfa
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DOI：
10.1016/j.cj.2020.11.009
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发表时间：
2021-01
期刊：
影响因子：
6.6
通讯作者：
Kexin Wang;Yanrong Liu;F. Teng;Huifang Cen;Jianping Yan;Shiwen Lin;Dayong Li;Wanjun Zhang
中科院分区：
文献类型：
--
作者：
Kexin Wang;Yanrong Liu;F. Teng;Huifang Cen;Jianping Yan;Shiwen Lin;Dayong Li;Wanjun Zhang
紫花苜蓿(Medicago sativaL.)是栽培最广泛的多年生豆科牧草作物。据报道，来自双子叶植物的microRNA156(MiR156)前体基因有助于改善紫花苜蓿的植株结构和非生物胁迫抗性。然而，关于来自单子叶物种的miR156前体基因是否在紫花苜蓿中发挥功能的报道尚未见报道。我们将miR156的两个串联前体基因riceOsa-MIR156band Osa-MIR156c(Osa-MIR156bc)导入紫花苜蓿。转基因(TG)紫花苜蓿中miR156基因的表达显著增强。与野生型相比，高表达miR156的转基因植株具有更多的枝条和叶片，并表现出更好的耐盐性和抗旱性。过表达miR156的植株株高略有下降，但花盆中生长的转基因植株的生物量仍有增加。降低酸性洗涤剂木质素(ADL)含量，提高粗蛋白含量，显着改善了转基因植株的饲草品质。MiR156过表达抑制了MsSPL6、MsSPL12和MsSPL13等可能的miR156靶基因在转基因植株中的表达，在干旱或盐胁迫下，所有受试MsSPLs的表达都会急剧增加。RNA测序表明，miR156的过表达通过多条途径影响了与非生物抗逆性和植物发育相关的基因的表达。首次报道了单子叶植物miR156前体基因在紫花苜蓿中的过表达，揭示了单子叶植物水稻miRNA156前体基因可能用于双子叶牧草遗传改良的功能。
Alfalfa (Medicago sativaL.) is the most widely cultivated perennial leguminous forage crop woldwide. MicroRNA156 (miR156) precursor genes from dicotyledonous species are reportedly useful for improving alfalfa plant architecture and abiotic stress resistance. However, there has been no report on whether a miR156 precursor gene from a monocotyledonous species functions in alfalfa. We introduced two tandem precursor genes of miR156, riceOsa-MIR156bandOsa-MIR156c(Osa-MIR156bc), into alfalfa. The expression of miR156 in the transgenic (TG) alfalfa was significantly elevated. Compared to wild-type plants, the TG plants overexpressing miR156 had more branches and leaves and showed improved salt and drought tolerance. Overexpression of miR156 slightly reduced plant height, but the biomass yield of TG plants grown in flowerpots was still increased. Forage quality of TG plants was markedly improved by reduction of acid detergent lignin (ADL) content and increase in crude protein content. The expression of the putative miR156 target genesMsSPL6, MsSPL12, andMsSPL13in TG plants was repressed by miR156 overexpression, and that of all testedMsSPLs would be sharply increased under drought or salt stress. RNA sequencing revealed that overexpression of miR156 affected the expression of genes associated with abiotic stress resistance and plant development in multiple pathways. This first report of overexpression of monocot miR156 precursors in alfalfa sheds light on the function of miRNA156 precursors from the monocot species rice that could be used for genetic improvement of the dicot forage crop alfalfa.