Genome-Wide Identification of the PMEI Gene Family in Tea Plant and Functional Analysis of CsPMEI2 and CsPMEI4 Through Ectopic Overexpression

Abstract

Pectin methylesterase inhibitor (PMEI) inhibits pectin methylesterase (PME) activity at post-translation level, which plays core roles in vegetative and reproductive processes and various stress responses of plants. However, the roles of PMEIs in tea plant are still undiscovered. Herein, a total of 51 CsPMEIs genes were identified from tea plant genome. CsPMEI1-4 transcripts were varied in different tea plant tissues and regulated by various treatments, including biotic and abiotic stresses, sugar treatments, cold acclimation and bud dormancy. Overexpression of CsPMEI4 slightly decreased cold tolerance of transgenic Arabidopsis associated with lower electrolyte leakage, soluble sugars contents and transcripts of many cold-induced genes as compared to wild type plants. Under long-day and short-day conditions, CsPMEI2/4 promoted early flowering phenotypes in transgenic Arabidopsis along with higher expression levels of many flowering-related genes. Moreover, overexpression of CsPMEI2/4 decreased PME activity, but increased sugars contents (sucrose, glucose, and fructose) in transgenic Arabidopsis as compared with wild type plants under short-day condition. These results indicate that CsPMEIs are widely involved in tea plant vegetative and reproductive processes, and also in various stress responses. Moreover, CsPMEI4 negatively regulated cold response, meanwhile, CsPMEI2/4 promoted early flowering of transgenic Arabidopsis via the autonomous pathway. Collectively, these results open new perspectives on the roles of PMEIs in tea plant.

Characterization of the genetic and regulatory networks associated with sugar and acid metabolism in apples via an integrated strategy

“…MdPMEI3 encodes a pectin esterase inhibitor that regulates the demethylation of pectin in apical meristematic tissues, thereby influencing protoplast formation and foliar structure patterns ( Lionetti et al., 2007 ). Overexpression of AtPMEI3 has been shown to promote HG hypermethylation and influences the formation of floral primordia ( Li et al., 2021 ). The hub gene MdFTSHC , detected in the “MEblue” module, is an ATP-dependent zinc metalloprotease containing an AAA (an ATPase associated with various cellular activities) and a Zn 2+ metalloprotease structural domain that plays a key role in the hydrolysis of membrane proteins ( Adam et al., 2005 ; Wagner et al., 2012 ).…”

Recent progress and perspectives on physiological and molecular mechanisms underlying cold tolerance of tea plants

“…PPME , pectinesterase-like PMEs ( PECTIN METHYLESTERASE INHIBITORs ) maintains apoplastic Ca 2+ -homeostasis, controlling stomatal movements and in regulating the flexibility of the guard cell wall ( Wu et al., 2018 ). Previous studies have also suggested that inhibiting the pectin methylesterase activity of tea plants, including Pectin Methylesterase Inhibitor 2 and 4 ( CsPMEI2 and CsPMEI4 ), slightly reduces the cold tolerance of transgenic Arabidopsis ( Li et al., 2021 ). XTHs (Xyloglucan endotransglucosylase/hydrolase) cuts and re-joins hemicellulose chains in Plant cell wall, contributing to wall assembly, affecting cellulose deposition ( Wu et al., 2018 ).…”

Genome-Wide Identification and Characterization of Calmodulin and Calmodulin-like Genes Family in Tea Plant and Their Roles under Abiotic Stress

“…Both CsCaM1 and CsCML7, 15, 21, 35, and 55 were highly expressed after 7 d of low-temperature stress. CsCML1, 4,25,33,36,37,40,41,43,44,50,56, and 57 showed the highest expression level after the de-acclimation (DA) treatment. However, the rest of the genes showed no expression in response to cold treatment.…”

“…The tea plant (Camellia sinensis) is an evergreen economic plant that grows well in normal temperature, high humidity, and acid soil (pH 4.5-5.5) environments [43]. However, due to the recent occurrence of extreme weather events, the tea plant typically cannot overwinter safely or grow healthily when damaged by drought, heat, salinity, low temperature, or cold spells.…”