SlTLFP8 reduces water loss to improve water‐use efficiency by modulating cell size and stomatal density via endoreduplication

Abstract

Improving plant water-use efficiency (WUE) is important to plant survival and crop yield in the context of water limitation. In this study, SlTLFP8 (Tubby-like F-box protein 8) was identified as an osmotic-induced gene in tomato. Transgenic tomato with up-regulated expression of SlTLFP8 showed enhanced water-deficient resistance, whereas knockout mutants generated by CRISPR/Cas9 were more sensitive to water deficit. SlTLFP8 overexpression significantly enhanced WUE by suppressing transpiration under both water-sufficient and water-deficient conditions. Further study showed that overexpressing SlTLFP8 significantly increased leaf epidermal cell size and thereby decreased stomatal density 10-20%, conversely SlTLFP8 knockout resulted in decreased cell size and thereby increased stomatal density 20-50%. SlTLFP8 overexpression and knockout modulated ploidy levels in leaf cells. Changes in expression of cell cycle related genes also indicated that SlTLFP8 affected cell size and stomatal density through endocycle transition. Despite changes in stomata density and transpiration, altering the expression of SlTLFP8 did not change photosynthesis. Additionally, biomass was not altered and there was little difference in fruit yield for transgenic and wild type lines under water-sufficient and water-deficient conditions. Our results demonstrate the effect of SlTLFP8 on endoreduplication and the potential of SlTLFP8 for improvement of WUE. Brief Summery This work found a new mechanism of TLP (Tubby like protein) response to waterdeficient stress. SlTLFP8, a member of TLP family, regulates water-deficient resistance by modulating water loss via affecting stomatal density. Expression of SlTLFP8 was induced by osmotic stress. Transgenic tomato lines with SlTLFP8 overexpression or SlTLFP8 knockout showed significantly differences in water-use efficiency (WUE) and water-deficient resistance. The difference of leaf water loss caused by transpiration is the main explanation of the difference in WUE and water-deficient resistance. Additionally, overexpressing SlTLFP8 significantly decreased stomatal density, while SlTLFP8 knockout resulted in increased stomatal density, and SlTLFP8 affected stomatal density through endoreduplication and altered epidermal cell size. Despite

A tubby-like protein CsTLP8 acts in the ABA signaling pathway and negatively regulates osmotic stresses tolerance during seed germination

“…Zhang et al explored the expression of SlTLPs in tomato fruit founded that SlTLP1, SlTLP2, SlTLP4 and SlTLP5 are ripening-related, and SlTLP1 and SlTLP2 may play a role in ethylene-dependent fruit ripening [30]. Our previous works imply that SlTLFP8 regulated stomatal density through nuclear endoreduplication and affected water-deficient resistance and water-use efficiency [31].…”

NAC Transcription Factor PwNAC11 Activates ERD1 by Interaction with ABF3 and DREB2A to Enhance Drought Tolerance in Transgenic Arabidopsis

“…Considering that ERD1 could be activated by ANAC019/ANAC072 in Arabidopsis [32], and the expression of ERD1 was prominently upregulated in PwNAC11 OE lines, we subsequently conducted the yeast one-hybrid (Y1H) assays to confirm the regulation of PwNAC11 on ERD1 promoter region. In contrast with the negative control, both pGADT7-PwNAC11 + pAbAi-ERD1pro and pGADT7-ABF3 + pAbAi-ERD1pro yeast strains could grow on SD/Ura-Leu + AbA selective medium (Figure S3), suggesting both Recent studies indicated that increased ABA content could promote stomatal closure to improve the drought tolerance of plants [31]. We further observed and calculated the level of close stomata by exogenously applying ABA in different lines.…”

Phytohormone-Based Regulation of Trichome Development

“…Endoreduplication has an important role in modulating plant organ or tissue size ( Peng et al, 2015 ; Li et al, 2020 ). Most studies on this topic have indicated that cyclin proteins are downstream target genes involved in organ size ( Breuer et al, 2009 , 2012 ).…”

“…It is therefore very important to reveal how genes reach the right state at the right place and at the right time. Although many RNA-seq techniques have been used to study the development of glandular trichomes (Li et al, 2020;Liao et al, 2020), progress in understanding glandular trichome development has been very slow. Since many glandular trichomes are multicellular, the function of each cell is different, resulting in different levels of mRNA in each cell.…”