MdPP2C24/37, Protein Phosphatase Type 2Cs from Apple, Interact with MdPYL2/12 to Negatively Regulate ABA Signaling in Transgenic Arabidopsis

Abstract

The phytohormone abscisic acid (ABA) plays an important role in the ability of plants to cope with drought stress. As core members of the ABA signaling pathway, protein phosphatase type 2Cs (PP2Cs) have been reported in many species. However, the functions of MdPP2Cs in apple (Malus domestica) are unclear. In this study, we identified two PP2C-encoding genes, MdPP2C24/37, with conserved PP2C catalytic domains, using sequence alignment. The nucleus-located MdPP2C24/37 genes were induced by ABA or mannitol in apple. Genetic analysis revealed that overexpression of MdPP2C24/37 in Arabidopsis thaliana led to plant insensitivity to ABA or mannitol treatment, in terms of inhibiting seed germination and overall seedling establishment. The expression of stress marker genes was upregulated in MdPP2C24/37 transgenic lines. At the same time, MdPP2C24/37 transgenic lines displayed inhibited ABA-mediated stomatal closure, which led to higher water loss rates. Moreover, when exposed to drought stress, chlorophyll levels decreased and MDA and H2O2 levels accumulated in the MdPP2C24/37 transgenic lines. Further, MdPP2C24/37 interacted with MdPYL2/12 in vitro and vivo. The results indicate that MdPP2C24/37 act as negative regulators in response to ABA-mediated drought resistance.

Metabolome and Transcriptome Analysis Revealed the Pivotal Role of Exogenous Melatonin in Enhancing Salt Tolerance in Vitis vinifera L.

“…Melatonin is an important biological molecule that interacts with a variety of substances during plant development, especially to help regulate adaptive plant responses to abiotic stresses. Existing studies suggest that melatonin treatment can enhance plant salt tolerance in tomatoes [3], apples [4], barley [5], and rice [6]. Melatonin treatment mediates tolerance to salt in cotton by adjusting Ca 2+ and reactive oxygen scavenging mechanisms [7].…”

“…Saline soil is a source of extremely harmful abiotic stress, which prolongs the time of seed germination and plant maturation and reduces the rate of seed setting [4]. Per the data as of 2021, there are millions of hectares of saline soil in China, and the large quantities of soluble salts in saline soil far exceed the range that crops can bear, and the existence of saline soil seems to be more common than ever before [5]. Under salt stress, plant growth, carbon dioxide uptake, and light energy conversion and utilization are all constrained [6], and the diminishment of the electron transport rate and the imbalance of ion homeostasis are exhibited [7].…”

“…A high-salt environment can stimulate disorders of a plant's internal environment. Among these disorders, salt has the most serious negative impact on plants [5]. To minimize damages caused by salt stress, plants launch a series of physiological and biochemical processes, including ion homeostasis and osmotic balance [8].…”

Physiological response and transcriptome analyses of leguminous Indigofera bungeana Walp. to drought stress

“…As a result of this interaction, SnRK2 was autophosphorylated, and ABA response element-binding factors (ABFs) were activated ( Devireddy et al, 2021 ). The PYR/PYL protien plays a role in sensing and signaling ABA, MdPP2C24/37 from apple transgenic lines showed inhibited ABA-mediated stomatal closure, thus led to higher water loss rates ( Liu et al, 2022a ; Liu et al, 2022b ). In this study, thirteen PP2C genes were upregulated in leaves, eight ABF DEGs were downregulated in the leaves, two SNF1-related protein kinase 2 (SnRK2) were downregulated in roots to response the ABA accumulation.…”

“…Other studies have shown that the cascade of MAPK induction by ABA regulates plant growth and development to improve plant drought tolerance. Liu et al (2022a) ; Liu et al (2022b) have shown ABA, ROS, and calcium ion (Ca 2+ ), played pivotal roles in controlling stomatal closure under drought conditions. In other words, H 2 O 2 was likely responsible for inducing RbohD overexpression, and OXI1 act as a response element for H 2 O 2 released from the respiratory burst, causing the expression of related genes by eliminating H 2 O 2 to maintain intracellular homeostasis ( Dietz, Turkan & Krieger-Liszkay, 2016 ).…”