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A Novel Role of Medicago truncatula KNAT3/4/5-like Class 2 KNOX Transcription Factors in Drought Stress Tolerance.

Authors :
Iannelli MA
Nicolodi C
Coraggio I
Fabriani M
Baldoni E
Frugis G
Source :
International journal of molecular sciences [Int J Mol Sci] 2023 Aug 11; Vol. 24 (16). Date of Electronic Publication: 2023 Aug 11.
Publication Year :
2023

Abstract

Class 2 KNOX homeobox transcription factors (KNOX2) play a role in promoting cell differentiation in several plant developmental processes. In Arabidopsis , they antagonize the meristematic KNOX1 function during leaf development through the modulation of phytohormones. In Medicago truncatula , three KNOX2 genes belonging to the KNAT3/4/5-like subclass ( Mt KNAT3/4/5-like or MtKNOX3-like ) redundantly works upstream of a cytokinin-signaling module to control the symbiotic root nodule formation. Their possible role in the response to abiotic stress is as-of-yet unknown. We produced transgenic M. truncatula lines, in which the expression of four MtKNOX3-like genes was knocked down by RNA interference. When tested for response to water withdrawal in the soil, RNAi lines displayed a lower tolerance to drought conditions compared to the control lines, measured as increased leaf water loss, accelerated leaf wilting time, and faster chlorophyll loss. Reanalysis of a transcriptomic M. truncatula drought stress experiment via cluster analysis and gene co-expression networks pointed to a possible role of MtKNOX3-like transcription factors in repressing a proline dehydrogenase gene ( MtPDH ), specifically at 4 days after water withdrawal. Proline measurement and gene expression analysis of transgenic RNAi plants compared to the controls confirmed the role of KNOX3-like genes in inhibiting proline degradation through the regulation of the MtPDH gene.

Details

Language :
English
ISSN :
1422-0067
Volume :
24
Issue :
16
Database :
MEDLINE
Journal :
International journal of molecular sciences
Publication Type :
Academic Journal
Accession number :
37628847
Full Text :
https://doi.org/10.3390/ijms241612668