Articles
Polygalacturonases gene family analysis identified FcPG12 as the key player in fig (Ficus carica L.) fruit softening
Article number
1405_17
Pages
165 – 182
Language
English
Abstract
Polygalacturonase (PG), an essential hydrolase responsible for pectin degradation, plays key role in fruit softening.
Fig (Ficus carica L.) is a high economic value fruit tree, however the fruit is of short shelf-life due to quick softening, and the PG gene and its regulators are not yet revealed.
In this study, 43 FcPG genes were identified in fig genome.
They are non-uniformly distributed on 13 chromosomes, tandem repeat PG gene clusters were found on chromosomes 4 and 5. Ka/Ks calculation and collinear analysis indicated purify selection was the main power of FcPG gene family expansion.
Fourteen FcPGs were found expression in fig fruits screened by FPKM values >10, of which 7 FcPGs were positively correlated with fruit softening and 3 were negatively correlated.
Eleven FcPGs were significantly upregulated and 2 downregulated in response to ethephon treatment. FcPG12, a member in the tandem repeat cluster of chromosome 4 was recruited by its sharp transcript abundance increment during fruit softening and significantly responsive to ethephon.
When FcPG12 was transiently overexpressed, the fig fruit firmness was decreased and the PG enzyme activity of the tissue was increased.
Two ethylene-responsive transcription factor (ERF) binding GCC-box sites were found on FcPG12 promoter.
Yeast one-hybrid and dual luciferase assay showed that FcERF5 directly bind to FcPG12 promoter and upregulated its expression.
Transient overexpression showed that FcERF5 upregulated the expression of FcPG12, which increased PG activity and led to fruit softening.
Our study identified FcPG12 as the key PG gene involved in fig fruit softening, and it is directly positively regulated by FcERF5, the results provided new information in exploring the molecular regulation of fig fruit softening.
Fig (Ficus carica L.) is a high economic value fruit tree, however the fruit is of short shelf-life due to quick softening, and the PG gene and its regulators are not yet revealed.
In this study, 43 FcPG genes were identified in fig genome.
They are non-uniformly distributed on 13 chromosomes, tandem repeat PG gene clusters were found on chromosomes 4 and 5. Ka/Ks calculation and collinear analysis indicated purify selection was the main power of FcPG gene family expansion.
Fourteen FcPGs were found expression in fig fruits screened by FPKM values >10, of which 7 FcPGs were positively correlated with fruit softening and 3 were negatively correlated.
Eleven FcPGs were significantly upregulated and 2 downregulated in response to ethephon treatment. FcPG12, a member in the tandem repeat cluster of chromosome 4 was recruited by its sharp transcript abundance increment during fruit softening and significantly responsive to ethephon.
When FcPG12 was transiently overexpressed, the fig fruit firmness was decreased and the PG enzyme activity of the tissue was increased.
Two ethylene-responsive transcription factor (ERF) binding GCC-box sites were found on FcPG12 promoter.
Yeast one-hybrid and dual luciferase assay showed that FcERF5 directly bind to FcPG12 promoter and upregulated its expression.
Transient overexpression showed that FcERF5 upregulated the expression of FcPG12, which increased PG activity and led to fruit softening.
Our study identified FcPG12 as the key PG gene involved in fig fruit softening, and it is directly positively regulated by FcERF5, the results provided new information in exploring the molecular regulation of fig fruit softening.
Publication
Authors
Y. Wang, Z.Y. Fan, Y.L. Zhai, H.T. Huang, H.Q. Ma
Keywords
fig (Ficus carica L.), polygalacturonase gene family, expression, ethylene response factor, fruit softening
Groups involved
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