VviPLATZ1 is a major factor that controls female flower morphology determination in grapevine

Pat Iocco-Corena,Harley M Smith,Laurent Torregrosa,Don Mackenzie,Mark R Thomas,Jamila Chaïb

doi:10.1038/s41467-021-27259-8

Abstract

Plant genetic sex determinants that mediate the transition to dioecy are predicted to be diverse, as this type of mating system independently evolved multiple times in angiosperms. Wild Vitis species are dioecious with individuals producing morphologically distinct female or male flowers; whereas, modern domesticated Vitis vinifera cultivars form hermaphrodite flowers capable of self-pollination. Here, we identify the VviPLATZ1 transcription factor as a key candidate female flower morphology factor that localizes to the Vitis SEX-DETERMINING REGION. The expression pattern of this gene correlates with the formation reflex stamens, a prominent morphological phenotype of female flowers. After generating CRISPR/Cas9 gene-edited alleles in a hermaphrodite genotype, phenotype analysis shows that individual homozygous lines produce flowers with reflex stamens. Taken together, our results demonstrate that loss of VviPLATZ1 function is a major factor that controls female flower morphology in Vitis.

Highlights

Plant genetic sex determinants that mediate the transition to dioecy are predicted to be diverse, as this type of mating system independently evolved multiple times in angiosperms
Three genetic mapping resources were genotyped with this SEX-DETERMINING REGION (SDR) SNP set: (1) Vitis vinifera cultivars with known flower sex genotypes (f/ f, H/f or H/H), (2) an F1 00C001V0008 (f/f) x Ugni Blanc (H/f) mapping population[37] and (3) self-fertilized hermaphrodite microvine (H/f) progenies (S1 to S5)
By using this genetic mapping strategy, the genotype information derived from the Vitis vinifera cultivars indicated that the 5′ boundary of the female sex-determining region (FSDR) was located in TPP, at the VvMT_54 SNP (Fig. 1b; Supplementary Data 1)

Summary

Introduction

Plant genetic sex determinants that mediate the transition to dioecy are predicted to be diverse, as this type of mating system independently evolved multiple times in angiosperms. Wild Vitis species are dioecious with individuals producing morphologically distinct female or male flowers; whereas, modern domesticated Vitis vinifera cultivars form hermaphrodite flowers capable of self-pollination. Actinidia and Asparagus are two species that exhibit a two-gene model of sex determination involving DNA polymorphisms that results in: (1) ectopic expression of a malepromoting factor that suppresses pistil formation and (2) a recessive mutation in a single gene required for tapetum development and pollen fertility[11,12,13,14]. In wild Vitis species, females initiate flowers that produce short reflex stamens that bend away from the receptive pistil, which likely reduces self-fertilization[18]. One hypothesis predicts that grape sex determination is mediated by the two-gene model[27,29,30] According to this hypothesis, female flower formation is mediated by a recessive mutation that controls stamen development. Domesticated hermaphrodite grapevines with an H/H or H/f genotype produce perfect flowers that contain a modified and less dominant Mfactor[27]

Methods

Results

Conclusion