Dahro Bachar, Wang Fei, Peng Ting, Liu Ji-Hong
Key Laboratory of Horticultural Plant Biology (MOE), College of Horticulture and Forestry Science, Huazhong Agricultural University, Wuhan, 430070, China.
Department of Horticulture, Faculty of Agriculture, Tishreen University, Lattakia, Syria.
BMC Plant Biol. 2016 Mar 29;16:76. doi: 10.1186/s12870-016-0761-0.
Alkaline/neutral invertase (A/N-INV), an enzyme that hydrolyzes sucrose irreversibly into glucose and fructose, is essential for normal plant growth,development, and stress tolerance. However, the physiological and/or molecular mechanism underpinning the role of A/N-INV in abiotic stress tolerance is poorly understood.
In this report, an A/N-INV gene (PtrA/NINV) was isolated from Poncirus trifoliata, a cold-hardy relative of citrus, and functionally characterized. PtrA/NINV expression levels were induced by cold, salt, dehydration, sucrose, and ABA, but decreased by glucose. PtrA/NINV was found to localize in both chloroplasts and mitochondria. Overexpression of PtrA/NINV conferred enhanced tolerance to multiple stresses, including cold, high salinity, and drought, as supported by lower levels of reactive oxygen species (ROS), reduced oxidative damages, decreased water loss rate, and increased photosynthesis efficiency, relative to wild-type (WT). The transgenic plants exhibited higher A/N-INV activity and greater reducing sugar content under normal and stress conditions.
PtrA/NINV is an important gene implicated in sucrose decomposition, and plays a positive role in abiotic stress tolerance by promoting osmotic adjustment, ROS detoxification and photosynthesis efficiency. Thus, PtrA/NINV has great potential to be used in transgenic breeding for improvement of stress tolerance.
碱性/中性转化酶（A/N-INV）是一种将蔗糖不可逆地水解为葡萄糖和果糖的酶，对植物正常生长、发育及胁迫耐受性至关重要。然而，A/N-INV在非生物胁迫耐受性中作用的生理和/或分子机制尚不清楚。
在本报告中，从柑橘属耐寒近缘种枳中分离出一个A/N-INV基因（PtrA/NINV）并对其进行功能表征。PtrA/NINV的表达水平受低温、盐、脱水、蔗糖和脱落酸诱导，但受葡萄糖抑制。发现PtrA/NINV定位于叶绿体和线粒体。与野生型（WT）相比，PtrA/NINV的过表达赋予了对多种胁迫（包括低温、高盐和干旱）更强的耐受性，表现为活性氧（ROS）水平较低、氧化损伤减少、失水率降低以及光合作用效率提高。转基因植物在正常和胁迫条件下均表现出较高的A/N-INV活性和较高的还原糖含量。
PtrA/NINV是一个参与蔗糖分解的重要基因，通过促进渗透调节、ROS解毒和光合作用效率在非生物胁迫耐受性中发挥积极作用。因此，PtrA/NINV在用于提高胁迫耐受性的转基因育种中具有巨大潜力。
