Characterization of vegetative inflorescence (mc-vin) mutant provides new insight into the role of MACROCALYX in regulating inflorescence development of tomato.

Fernando J Yuste-Lisbona,Muriel Quinet,Trinidad Angosto,Antonia Fernández-Lozano,Benito Pineda,Rafael Lozano,Vicente Moreno

doi:10.1038/srep18796

Abstract

Inflorescence development is a key factor of plant productivity, as it determines flower number. Therefore, understanding the mechanisms that regulate inflorescence architecture is critical for reproductive success and crop yield. In this study, a new mutant, vegetative inflorescence (mc-vin), was isolated from the screening of a tomato (Solanum lycopersicum L.) T-DNA mutant collection. The mc-vin mutant developed inflorescences that reverted to vegetative growth after forming two to three flowers, indicating that the mutated gene is essential for the maintenance of inflorescence meristem identity. The T-DNA was inserted into the promoter region of the MACROCALYX (MC) gene; this result together with complementation test and expression analyses proved that mc-vin is a new knock-out allele of MC. Double combinations between mc-vin and jointless (j) and single flower truss (sft) inflorescence mutants showed that MC has pleiotropic effects on the reproductive phase, and that it interacts with SFT and J to control floral transition and inflorescence fate in tomato. In addition, MC expression was mis-regulated in j and sft mutants whereas J and SFT were significantly up-regulated in the mc-vin mutant. Together, these results provide new evidences about MC function as part of the genetic network regulating the development of tomato inflorescence meristem.

Highlights

Life Institute, Université catholique de Louvain, Croix du Sud 4-5 bte L7.07.13, B-1348 Louvain-la-Neuve, Belgium. *These authors contributed to this work
As part of a systematic analysis of gene function involved in tomato reproductive development, the vegetative inflorescence mutant was isolated from the screening of a collection of T2 segregating T-DNA lines generated from the tomato cultivar Moneymaker (MM)
It was previously hypothesized that J could interact with a MADS-box protein induced by systemic SFT protein to prevent vegetative growth in the IM8,11

Summary

Introduction

Life Institute, Université catholique de Louvain, Croix du Sud 4-5 bte L7.07.13, B-1348 Louvain-la-Neuve, Belgium. *These authors contributed to this work. SM generally produces three leaves before terminating with a new inflorescence This growth pattern is repeated by the formation of successive determinate units or sympodial segments; the architecture of a tomato plant means a regular alternation of vegetative and reproductive phases resulting from the newly arisen SM (reviewed in[7]). The anantha (an) mutant produces inflorescences reminiscent of the common cauliflower[14] and the compound inflorescence (s) mutant inflorescences are highly branched, but eventually bear up to 200 fertile flowers[9,15] Both AN and S were suggested to control inflorescence architecture by promoting successive stages in the progression of an IM to FM9. This report showed the molecular and functional characterization of a new tomato T-DNA mutant, vegetative inflorescence (mc-vin), which displayed a reversion of the IM to vegetative growth after producing a few flowers with homeotic conversion from sepals to leaf-like structures. Results indicate that MC is a crucial component of the genetic pathway regulating inflorescence development of tomato, and that this function is exerted through its interaction with SFT and J genes

Methods

Results

Conclusion