Evaluating the kinetics of root growth and floral development in transgenic plants with altered levels of NtRH35 (NtDDX35) expression

• Grant number: 23/02900-0
• Support Opportunities: Regular Research Grants
• Start date: July 01, 2023
• End date: December 31, 2025
• Field of knowledge: Biological Sciences - Genetics - Plant Genetics
• Agreement: CNPq
• Principal Investigator: Maria Helena de Souza Goldman
• Grantee: Maria Helena de Souza Goldman
• Host Institution: Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto (FFCLRP). Universidade de São Paulo (USP). Ribeirão Preto , SP, Brazil
• Associated research grant: 19/24774-1 - The importance of the SCI1 gene in the floral meristem, its transcriptional regulation and evolutionary conservation, AP.TEM
• Associated scholarship(s): 23/12687-2 - Study of floral development and root growth kinetics in transgenic plants with altered levels of NtRH35 (NtDDX35) expression, BP.JD

Abstract

Previous work by our group (FAPESP 16/20486-3) identified a new protein, not yet characterized in plants, as an interaction partner of SCI1 (Stigma/style Cell-cycle Inhibitor 1) in Nicotiana tabacum. This protein is similar to RNA helicases of the DEAD-box type and was named NtDDX35 or NtRH35. To study the function of the NtRH35 coding gene, which is expressed in all plant organs, transgenic plants were produced with overexpression of this gene (NtRH35-OE), as well as its silencing via RNAi (NtRH35-Ri) (Pinoti, 2021 ). In preliminary analyses, contrasting phenotypes were observed regarding the growth and vegetative and floral development of transgenic plants in relation to control plants (WT). Plants with NtRH35 silencing are shorter than the wild-type (WT) genotype and have difficulty completing floral development. Overexpression plants have height, stem thickness, as well as apparently larger organs. These contrasting phenotypes in the NtRH35 transgenics suggest a role in controlling cell division and/or expansion. In order to understand which mechanisms lead to these phenotypes, in this project we aim to evaluate cell cycle kinetics and acquire absolute measurements of cell size and volume, which will be taken during root growth. Additionally, we will evaluate the floral development in different lines of transgenic plants with altered levels of NtRH35 expression. To achieve these goals, modern bioimaging techniques will be used, such as 5-ethynyl-2 deoxyuridine (EdU) labeling combined with two-photon microscopy, in addition to transmitted light microscopy analyses. (AU)