茶树fibrillin基因家族全基因组鉴定及CsFBN1和CsFBN4功能分析

Abstract

Fibrillins (FBNs) are proteins associated with lipid metabolism and are localized to plastoglobules (PGs), and participates in multiple physiological processes in plants, including stress responses, growth, and development. In the present study, 14 CsFBN genes were identified from the tea plant ( Camellia sinensis (L.) Kuntze) genome, and phylogenetic analysis indicated that these CsFBNs were distributed across 10 subfamilies. PAP domains were present in all CsFBN proteins, whereas CsFBN2b, CsFBN11a, and CsFBN11b contained additional distinctive domains. Transcriptome analysis showed that CsFBN1 and CsFBN4 were highly expressed in old leaves, and their expression increased with leaf maturity. Under drought treatment, CsFBN1 , CsFBN2a , CsFBN2c , and CsFBN9 were significantly upregulated, especially CsFBN1 . A pronounced transcriptional response of CsFBN1 was also observed under shading and salt stress. The significant upregulation was also detected for most CsFBN genes after abscisic acid (ABA) treatment. Subcellular localization analyses indicated that most CsFBN proteins were located to chloroplasts. Virus-induced gene silencing (VIGS) was then used to suppress CsFBN1 and CsFBN4 expression, and no obvious changes in leaf phenotype were detected in silenced plants. However, a moderate decrease in PG size and number was observed in CsFBN1 -silenced leaves, and the total PG area was significantly reduced in one CsFBN1 -silenced line (pTRV2- CsFBN1 -n). Silencing of CsFBN4 also markedly reduced PG number and total PG area in tea leaves. These results provide a basis for further functional characterization of FBNs in leaf development and stress tolerance in plants.