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Shy Girl , a kiwifruit suppressor of feminization, restricts gynoecium development via regulation of cytokinin metabolism and signalling
Author(s) -
VarkonyiGasic Erika,
Wang Tianchi,
Cooney Janine,
Jeon Subin,
Voogd Charlotte,
Douglas Mikaela J.,
Pilkington Sarah M.,
Akagi Takashi,
Allan Andrew C.
Publication year - 2021
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/nph.17234
Subject(s) - biology , gynoecium , cytokinin , outcrossing , botany , gene , actinidia chinensis , microbiology and biotechnology , genetics , pollen , stamen , auxin
Summary Kiwifruit ( Actinidia chinensis ) is a dioecious, long‐living woody perennial vine. Reduced generation time and induction of hermaphroditism can accelerate crop improvement and facilitate alternative farming for better food security in the face of climate change. Previous studies identified that CENTRORADIALIS genes CEN and CEN4 act to repress flowering, whilst the male‐specific Shy Girl ( SyGl ) gene with homology to type‐C cytokinin response regulators could repress gynoecium development in model plants. Here we use CRISPR/Cas9 to mutagenize CEN , CEN4 and SyGl in the male kiwifruit A. chinensis ‘Bruce’. Biallelic mutations of CEN and CEN4 generated rapid‐flowering male plants, and simultaneous targeting of CEN4 and SyGl gave rise to rapid‐flowering hermaphrodites with restored gynoecial function and viable pollen, providing functional evidence for the role of SyGl in suppression of feminization. Analysis of ovary tissues identified genes that contribute to carpel development and revealed that SyGl affected both cytokinin profiles and the expression of genes involved in cytokinin metabolism and signalling. The plant lines generated by CEN4/SyGl knockout could self‐pollinate and produce fast‐flowering offspring. These results establish that SyGI acts as the suppressor of feminization in kiwifruit and demonstrate the potential for accelerated breeding in an outcrossing horticultural woody perennial.