A 3‑Ketoacyl-CoA Synthase 10 (KCS10) Homologue from Alfalfa Enhances Drought Tolerance by Regulating Cuticular Wax Biosynthesis

Cuticular wax, forming the first line of defense against
adverse
environmental stresses, comprises very long-chain fatty acids (VLCFAs)
and their derivatives. 3-Ketoacyl-CoA synthase (KCS) is a rate-limiting
enzyme for VLCFA biosynthesis. In this study, we isolated KCS10, a KCS gene from alfalfa, and analyzed
the effect of gene expression on wax production and drought stress
in transgenic plants. MsKCS10 overexpression increased
compact platelet-like crystal deposition and promoted primary alcohol
biosynthesis through acyl reduction pathways in alfalfa leaves. Overexpression
of MsKCS10 induced the formation of coiled-rodlet-like
crystals and increased n-alkane content through decarbonylation
pathways in tobacco and tomato fruits. Overexpression of MsKCS10 enhanced drought tolerance by limiting nonstomatal water loss, improving
photosynthesis, and maintaining osmotic potential under drought stress
in transgenic tobacco. In summary, MsKCS10 plays
an important role in wax biosynthesis, wax crystal morphology, and
drought tolerance, although the mechanisms are different among the
plant species. MsKCS10 can be targeted in future
breeding programs to improve drought tolerance in plants.

表皮蜡质，作为抵御恶劣环境压力的第一道防线，由非常长的链脂肪酸（VLCFAs）及其衍生物构成。3-酮酰基辅酶A合酶（KCS）是VLCFA生物合成的限速酶。在本研究中，我们从首鸢草中分离出KCS10基因，并分析了基因表达对转基因植物蜡质产量和干旱胁迫的影响。MsKCS10的过表达促进了紧密的板状晶体样沉积，并通过酰基还原途径在首鸢草叶片中促进了初级醇的生物合成。MsKCS10的过表达在烟草和番茄果实中诱导了螺旋棒状晶体的形成，并通过脱羧途径增加了n-烷烃含量。MsKCS10的过表达通过限制非气孔水分丧失、提高光合作用以及维持干旱胁迫下的渗透势，增强了转基因烟草的抗旱性。总之，MsKCS10在蜡质生物合成、蜡质晶体形态以及抗旱性方面发挥着重要作用，尽管在不同植物物种中其作用机制各异。MsKCS10有望在未来育种计划中被靶向利用，以提高植物的抗旱性。