Abstract: Flowering plants have evolved intricate yet adaptable sex determination systems to increase genetic diversity and fitness of the offspring. Understanding sex determination is vital in agriculture, as it determines how crops are cultivated and bred. The global food security is threatened by climate change, pollinator decline, and rising demand. In this post-genomic era, the discovery and optimization of gene networks governing key agricultural traits hold the promise to significantly boost productivity. During my postdoc, I investigated how female flowers evolved from ancestral hermaphroditism in cucurbits. We discovered a mechanism in melon where a versatile phytohormone, ethylene, produced in the carpel primordia is perceived in the stamen primordia through spatially differentially expressed ethylene receptors. Subsequently, the CmEIN3/CmEIL1 signalling module in stamen primordia activates the expression of CmHB40, a homeodomain transcription factor. The expression of CmHB40 in stamen primordia of female flowers leads to the downregulation of key genes required for stamen development and upregulates genes associated with plant organ senescence. Our investigation of melon genetic biodiversity revealed a haplotype, originating in Africa, altered in EIN3/EIL1 binding to CmHB40 promoter and associated with bisexual flower development. Unlike other bisexual mutants in cucurbits, CmHB40 mutations do not alter fruit shape. By disentangling the role of ethylene in fruit shape and sex determination pathways, our work opens new avenues in plant breeding. My future research will focus on identifying key regulators of sex determination and fruit set in orphan cucurbits cultivated in India. These crops are integral to both food security and income generation for underprivileged farmers. By harnessing these regulators, we aim to engineer plant lines that overcome the challenges associated with cultivating these open-pollinated cucurbit crops.

Meeting ID: 924 3151 9201
Passcode: 979996