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The role of Fa BG 3 in fruit ripening and B. cinerea fungal infection of strawberry
Author(s) -
Li Qian,
Ji Kai,
Sun Yufei,
Luo Hao,
Wang Hongqing,
Leng Ping
Publication year - 2013
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1111/tpj.12272
Subject(s) - ripening , botrytis cinerea , abscisic acid , rna interference , biology , gene , gene expression , abiotic stress , fungus , botany , horticulture , biochemistry , rna
Summary In plants, β–glucosidases ( BG ) have been implicated in developmental and pathogen defense, and are thought to take part in abscisic acid ( ABA ) synthesis via hydrolysis of ABA glucose ester to release active ABA ; however, there is no genetic evidence for the role of BG genes in ripening and biotic/abiotic stress in fruits. To clarify the role of BG genes in fruit, eight Fa/Fv BG genes encoding β–glucosidase were isolated using information from the GenBank strawberry nucleotide database. Of the Fa/Fv BG genes examined, expression of Fa BG 3 was the highest, showing peaks at the mature stage, coincident with the changes observed in ABA content. To verify the role of this gene, we suppressed the expression of Fa BG 3 via inoculation with Agrobacterium tumefaciens containing tobacco rattle virus carrying a Fa BG 3 fragment ( RNA i). The expression of Fa BG 3 in Fa BG 3 ‐ RNA i‐treated fruit was markedly reduced, and the ABA content was lower than that of the control. Fa BG 3 ‐ RNA i‐treated fruit did not exhibit full ripening, and were firmer, had lower sugar content, and were pale compared with the control due to down‐regulation of ripening‐related genes. Fa BG 3 ‐ RNA i‐treated fruit with reduced ABA levels were much more resistant to Botrytis cinerea fungus but were more sensitive to dehydration stress than control fruit. These results indicate that Fa BG 3 may play key roles in fruit ripening, dehydration stress and B. cinerea fungal infection in strawberries via modulation of ABA homeostasis and transcriptional regulation of ripening‐related genes.