Affiliation:
1. College of Horticulture, State Key Laboratory of Crop Genetics & Germplasm Enhancement and Utilization Nanjing Agricultural University Nanjing Jiangsu China
2. The New Zealand Institute for Plant and Food Research Ltd, Mt Albert Research Centre Auckland New Zealand
3. College of Horticultural Science and Engineering Shandong Agricultural University, Taian Shandong China
Abstract
SummaryStone cells are often present in pear fruit, and they can seriously affect the fruit quality when present in large numbers. The plant growth regulator NAA, a synthetic auxin, is known to play an active role in fruit development regulation. However, the genetic mechanisms of NAA regulation of stone cell formation are still unclear. Here, we demonstrated that exogenous application of 200 μM NAA reduced stone cell content and also significantly decreased the expression level of PbrNSC encoding a transcriptional regulator. PbrNSC was shown to bind to an auxin response factor, PbrARF13. Overexpression of PbrARF13 decreased stone cell content in pear fruit and secondary cell wall (SCW) thickness in transgenic Arabidopsis plants. In contrast, knocking down PbrARF13 expression using virus‐induced gene silencing had the opposite effect. PbrARF13 was subsequently shown to inhibit PbrNSC expression by directly binding to its promoter, and further to reduce stone cell content. Furthermore, PbrNSC was identified as a positive regulator of PbrMYB132 through analyses of co‐expression network of stone cell formation‐related genes. PbrMYB132 activated the expression of gene encoding cellulose synthase (PbrCESA4b/7a/8a) and lignin laccase (PbrLAC5) binding to their promotors. As expected, overexpression or knockdown of PbrMYB132 increased or decreased stone cell content in pear fruit and SCW thickness in Arabidopsis transgenic plants. In conclusion, our study shows that the ‘PbrARF13‐PbrNSC‐PbrMYB132’ regulatory cascade mediates the biosynthesis of lignin and cellulose in stone cells of pear fruit in response to auxin signals and also provides new insights into plant SCW formation.
Funder
National Natural Science Foundation of China
Earmarked Fund for China Agriculture Research System
Subject
Plant Science,Agronomy and Crop Science,Biotechnology
Cited by
5 articles.
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