Gene network associates with CsCRC regulating fruit elongation in cucumber
Gen Che, Weiyuan Song, Xiaolan Zhang
Abstract
In cucumber (<italic>Cucumis sativus</italic> L.), fruit length is a crucial agronomic trait that affects appearance quality and crop yield. Different cucumber germplasms exhibit a large variation in fruit length, and the underlying candidate genes and regulatory mechanisms need to be further characterized. Recently we showed that an essential gene in modulating the cucumber fruit length, the YABBY transcription factor CRABS CLAW (CsCRC), activates its downstream target gene auxin responsive protein <italic>CsARP1</italic> to promote cell expansion and fruit elongation. Here, we show that auxin activity and three fruit development-related genes are involved in the CsCRC-regulated gene network in cucumber. We found that a PHYTOCHROME INTERACTING FACTOR (CsPIF1) protein elevates <italic>CsCRC</italic> transcription by directly binding to its promoter. The protein interaction assays showed that a reproductive YABBY transcription factor INNER NO OUTER (CsINO) and a bHLH protein SPATULA (CsSPT1) have direct interaction with CsCRC, suggesting their redundant role in cucumber fruit development.