posted on 2023-12-14, 21:06authored byHeng Wang, Hongjun Yu, Lin Chai, Tao Lu, Yang Li, Weijie Jiang, Qiang Li
Low light (LL) stress adversely affects plant growth
and productivity.
The role of exogenous sucrose in enhancing plant LL tolerance was
investigated by spraying sucrose on tomato (Solanum
lycopersicum L.) leaves. This study employed physiological
and molecular approaches to identify the underlying mechanisms. Exogenous
sucrose activated sucrose hydrolysis-related enzyme activity and upregulated
genes encoding sucrose and hexose transporters in mature leaves, decreasing
endogenous sucrose levels and promoting sucrose unloading during LL.
Stem-related genes associated with sucrose synthesis and transport
were also upregulated, enhancing sucrose phloem loading. Furthermore,
sucrose from stems activated sucrose unloading in sink leaves, forming
a feed-forward loop to sustain sucrose flow during LL. This led to
increased nonstructural carbohydrates (NSCs), improved energy metabolism,
and enhanced protein synthesis in leaves, ultimately boosting photosynthesis
and fruit yield after light recovery. These findings highlight how
exogenous sucrose enhances LL tolerance in tomatoes by increasing
the transport of NSCs from stems to leaves.