Cold acclimation can specifically inhibit chlorophyll biosynthesis in young leaves of Pakchoi

BMC Plant Biology

Lingyun Yuan¹  Hefang Zhou²  Xilin Hou³  Zhubo Li³  Tongkun Liu³  Huiyu Wang³ 

[1] College of Horticulture, Vegetable Genetics and Breeding Laboratory, Anhui Agricultural University, 230036, Hefei, China;Huainan Agricultural Science Institute, 232001, Huainan, China;State Key Laboratory of Crop Genetics and Germplasm Enhancement, Key Laboratory of Biology and Genetic Improvement of Horticultural Crops in East China, Ministry of Agriculture and Rural Affairs of the P.R. China, Engineering Research Center of Germplasm Enhancement and Utilization of Horticultural Crops, Nanjing Agricultural University, 210095, Nanjing, China;

关键词: 5-aminolevulinic acid (ALA);    BrFLU;    Chlorophyll biosynthesis;    Cold acclimation;    Leaf color conversion;    Pakchoi;   

DOI  :  10.1186/s12870-021-02954-2

来源: Springer

【 摘 要 】

BackgroundLeaf color is an important trait in breeding of leafy vegetables. Y-05, a pakchoi (Brassica rapa ssp. chinensis) cultivar, displays yellow inner (YIN) and green outer leaves (GOU) after cold acclimation. However, the mechanism of this special phenotype remains elusive.ResultsWe assumed that the yellow leaf phenotype of Y-05 maybe caused by low chlorophyll content. Pigments measurements and transmission electron microscopy (TEM) analysis showed that the yellow phenotype is closely related with decreased chlorophyll content and undeveloped thylakoids in chloroplast. Transcriptomes and metabolomes sequencing were next performed on YIN and GOU. The transcriptomes data showed that 4887 differentially expressed genes (DEGs) between the YIN and GOU leaves were mostly enriched in the chloroplast- and chlorophyll-related categories, indicating that the chlorophyll biosynthesis is mainly affected during cold acclimation. Together with metabolomes data, the inhibition of chlorophyll biosynthesis is contributed by blocked 5-aminolevulinic acid (ALA) synthesis in yellow inner leaves, which is further verified by complementary and inhibitory experiments of ALA. Furthermore, we found that the blocked ALA is closely associated with increased BrFLU expression, which is indirectly altered by cold acclimation. In BrFLU-silenced pakchoi Y-05, cold-acclimated leaves still showed green phenotype and higher chlorophyll content compared with control, meaning silencing of BrFLU can rescue the leaf yellowing induced by cold acclimation.ConclusionsOur findings suggested that cold acclimation can indirectly promote the expression of BrFLU in inner leaves of Y-05 to block ALA synthesis, resulting in decreased chlorophyll content and leaf yellowing. This study revealed the underlying mechanisms of leaves color change in cold-acclimated Y-05.

【 授权许可】

CC BY