SlCV affects starch metabolism by regulating SlBAM3 stability under low night temperature stress in tomatoes

Area of Science:

• Plant Biology
• Molecular Biology
• Biochemistry

Background:

• Nocturnal starch remobilization is vital for plant carbon allocation and stress adaptation.
• Beta-amylase 3 (BAM3) is the primary enzyme for starch degradation at night, but its stress-related regulation is unclear.
• Chloroplast vesiculation (CV) protein maintains chloroplast homeostasis under stress, but its role in starch metabolism is unknown.

Purpose of the Study:

• To investigate the role of chloroplast vesiculation (CV) protein in regulating starch metabolism under low night temperature (LNT) stress.
• To elucidate the interaction between SlCV and SlBAM3 in tomato plants under cold stress.
• To understand the contribution of SlCV-mediated regulation of SlBAM3 to plant tolerance against LNT stress.

Main Methods:

• Low night temperature (LNT) stress application on tomato plants.
• Genetic manipulation of SlCV and SlBAM3 expression (overexpression, silencing, knockout).
• RNA-sequencing (RNA-seq), metabolome analysis, and protein-protein interaction assays.

Main Results:

• SlCV overexpression exacerbated LNT-induced starch accumulation and reduced cold tolerance, while SlCV silencing promoted starch catabolism.
• SlCV physically interacts with SlBAM3, and SlCV overexpression accelerates SlBAM3 degradation under LNT stress.
• SlBAM3 overexpression enhanced cold tolerance, and SlBAM3 complementation rescued the LNT hypersensitivity of SlCV overexpression plants.

Conclusions:

• SlCV negatively regulates starch remobilization under LNT stress by promoting SlBAM3 degradation.
• The SlCV-SlBAM3 interaction is a key regulatory mechanism controlling starch metabolism and cold tolerance in tomato.
• This study provides novel insights into plant adaptation to cold stress through the regulation of starch metabolic pathways.