Regon, P. | Search bioRxiv

bioRxiv2025

ELIP is preferentially expressed in stomatal guard cells and has a role in stomatal opening upon transition to light

Plant early light-induced proteins (ELIPs) are chlorophyll-binding thylakoid membrane proteins commonly believed to function in photoprotection. However, results of studies with mutants or transgenic plants have been contradictory regarding this function, and the mechanistic workings of ELIPs have mostly remained elusive. We studied: (1) ELIP function in tomato (Solanum lycoperiscum) by generation and photosynthetic/physiological characterization of slelip mutants under various light conditions; and (2) ELIP tissue/cell localization by monitoring expression of the Venus yellow fluorescent protein fused to the native SlELIP1 promoter ( pSlELIP1::Venus) in transgenic tomato. Notably, slelip mutants did not display compromised photosynthetic performance and were not more sensitive to photoinhibition compared to parental plants, even following direct sunlight exposure. Surprisingly, pSlELIP1::Venus fusions revealed preferential expression in the leaf epidermis and specifically in stomatal guard cells, with no apparent expression in the mesophyll. No major alterations were observed in leaf gas exchange in slelip mutants at different light conditions. Intriguingly, stomatal conductance was reduced in slelip mutants upon the transition from dark to light. We propose an alternative hypothesis for plant ELIPs as players in the response of guard cells to light, connecting chlorophyll to stomatal function, and presenting a novel research direction for these enigmatic proteins.

plant biology↗

bioRxiv2021

Transcriptomic analysis revealed reactive oxygen species scavenging mechanisms associated with ferrous iron toxicity in aromatic Keteki Joha rice

Lowland acidic soils with water-logged regions are often affected by ferrous iron (Fe2+) toxicity, a major yield-limiting factor of rice production. The Reactive Oxygen Species (ROS) was hypothesized to be crucial under severe Fe2+ toxicity conditions. However, molecular mechanisms and associated ROS homeostasis genes are still not well-explored. In this study, a comparative RNA-Seq based transcriptome analysis was conducted to understand the Fe2+ toxicity tolerance mechanism in aromatic Keteki Joha. About 69 Fe homeostasis related genes and their homologs were identified, where most of the genes were downregulated. Differentially expressed genes (DEGs) are associated with biological processes-response to stress, stimulus and abiotic stimulus. DEGs involved in the Biosynthesis of amino acids, RNA degradation, Glutathione metabolism etc. were induced, whereas, Phenylpropanoid biosynthesis, Photosynthesis, and Fatty acid elongation were inhibited. The Mitochondrial iron transporter (OsMIT), Vacuolar Iron Transporter 2 (OsVIT2), Ferritin (OsFER), Vacuolar Mugineic Acid Transporter (OsVMT), Phenolic Efflux Zero1 (OsPEZ1), Root Meander Curling (OsRMC), Nicotianamine synthase (OsNAS3), etc. were upregulated in different tissues suggesting the importance of Fe retention and sequestration for detoxification. However, several antioxidants, ROS scavenging genes and abiotic stress-responsive transcription factors indicate ROS homeostasis as one of the most important defense mechanisms under severe Fe2+ toxicity. The CAT, GSH, APX, MDHAR, DHAR, GR were upregulated. Moreover, abiotic stress-responsive transcription factors NAC, MYB, ARF, bZIP, WRKY, C2H2-ZFP were also upregulated. Accordingly, ROS homeostasis has been proposed to be an important defense mechanism under such conditions. Thus, our results will enrich the knowledge of understanding Fe-homeostasis in rice.

genomics↗