Bai Danfeng, Li Zhi, Gu Shichao, Li Qiaohong, Sun Leiming, Qi Xiujuan, Fang Jinbao, Zhong Yunpeng, Hu Chungen
Key Laboratory for Fruit Tree Growth, Development and Quality Control, Zhengzhou Fruit Research Institute, Chinese Academy of Agricultural Sciences, Zhengzhou 450009, China.
Key Laboratory of Horticultural Plant Biology, College of Horticulture & Forestry Science, Huazhong Agricultural University, Wuhan 430070, China.
Plants (Basel). 2022 Aug 12;11(16):2098. doi: 10.3390/plants11162098.
Kiwifruit is commonly sensitive to waterlogging stress, and grafting onto a waterlogging-tolerant rootstock is an efficient strategy for enhancing the waterlogging tolerance of kiwifruit plants. KR5 () is more tolerant to waterlogging than 'Hayward' () and is a potential resistant rootstock for kiwifruit production. Here, we focused on evaluating the performance of the waterlogging-sensitive kiwifruit scion cultivar 'Zhongmi 2' when grafted onto KR5 (referred to as ZM2/KR5) and Hayward (referred to as ZM2/HWD) rootstocks, respectively, under waterlogging stress. The results showed 'Zhongmi 2' performed much better when grafted onto KR5 than when grafted onto 'Hayward', exhibiting higher photosynthetic efficiency and reduced reactive oxygen species (ROS) damage. Furthermore, the roots of ZM2/KR5 plants showed greater root activity and energy supply, lower ROS damage, and more stable osmotic adjustment ability than the roots of ZM2/HWD plants under waterlogging stress. In addition, we detected the expression of six key genes involved in the kiwifruit waterlogging response mechanism, and these genes were remarkably induced in the ZM2/KR5 roots but not in the ZM2/HWD roots under waterlogging stress. Moreover, principal component analysis (PCA) further demonstrated the differences in the physiological responses of the ZM2/KR5 and ZM2/HWD plants under waterlogging stress. These results demonstrated that the KR5 rootstock can improve the waterlogging tolerance of grafted kiwi plants by regulating physiological and biochemical metabolism and molecular responses.
猕猴桃通常对涝渍胁迫敏感，嫁接到耐涝砧木上是提高猕猴桃植株耐涝性的有效策略。KR5（）比‘海沃德’（）更耐涝，是猕猴桃生产中一种潜在的抗性砧木。在此，我们着重评估了涝渍敏感型猕猴桃接穗品种‘中猕2号’分别嫁接到KR5（简称ZM2/KR5）和‘海沃德’（简称ZM2/HWD）砧木上后在涝渍胁迫下的表现。结果表明，‘中猕2号’嫁接到KR5上时的表现远优于嫁接到‘海沃德’上时，表现出更高的光合效率和更低的活性氧（ROS）损伤。此外，在涝渍胁迫下，ZM2/KR5植株的根系比ZM2/HWD植株的根系表现出更强的根系活力和能量供应、更低的ROS损伤以及更稳定的渗透调节能力。另外，我们检测了参与猕猴桃涝渍响应机制的六个关键基因的表达，在涝渍胁迫下，这些基因在ZM2/KR5根系中显著上调，但在ZM2/HWD根系中未上调。此外，主成分分析（PCA）进一步证明了ZM2/KR5和ZM2/HWD植株在涝渍胁迫下生理反应的差异。这些结果表明，KR5砧木可通过调节生理生化代谢和分子反应来提高嫁接猕猴桃植株的耐涝性。
