Heat stress differentially modifies ethylene biosynthesis and signaling in pea floral and fruit tissues

Abstract

Ethylene biosynthesis is regulated in reproductive tissues in response to heat stress in a manner to optimize resource allocation to pollinated fruits with developing seeds. High temperatures during reproductive development are particularly detrimental to crop fruit/seed production. Ethylene plays vital roles in plant development and abiotic stress responses; however, little is known about ethylene's role in reproductive tissues during development under heat stress. We assessed ethylene biosynthesis and signaling regulation within the reproductive and associated tissues of pea during the developmental phase that sets the stage for fruit-set and seed development under normal and heat-stress conditions. The transcript abundance profiles of PsACS [encode enzymes that convert S-adenosyl-L-methionine to 1-aminocyclopropane-1-carboxylic acid (ACC)] and PsACO (encode enzymes that convert ACC to ethylene), and ethylene evolution were developmentally, environmentally, and tissue-specifically regulated in the floral/fruit/pedicel tissues of pea. Higher transcript abundance of PsACS and PsACO in the ovaries, and PsACO in the pedicels was correlated with higher ethylene evolution and ovary senescence and pedicel abscission in fruits that were not pollinated under control temperature conditions. Under heat-stress conditions, up-regulation of ethylene biosynthesis gene expression in pre-pollinated ovaries was also associated with higher ethylene evolution and lower retention of these fruits. Following successful pollination and ovule fertilization, heat-stress modified PsACS and PsACO transcript profiles in a manner that suppressed ovary ethylene evolution. The normal ethylene burst in the stigma/style and petals following pollination was also suppressed by heat-stress. Transcript abundance profiles of ethylene receptor and signaling-related genes acted as qualitative markers of tissue ethylene signaling events. These data support the hypothesis that ethylene biosynthesis is regulated in reproductive tissues in response to heat stress to modulate resource allocation dynamics.

Selenium and silica nanostructure-based recovery of strawberry plants subjected to drought stress

“…Drought stress decreased the firmness of strawberry fruits but spraying of nanoparticles increased this factor in plants under drought stress and normal conditions. This response could be due to the induction of ethylene production in fruits under drought stress 64 . Due to adjusting the expression of genes and enzymes involved in reactions related to cell walls, ethylene affects fruit firmness.…”

The Pivotal Role of Ethylene in Plant Growth

“…Importantly, ethylene is produced in response to multiple environmental stresses ( Figure 1 ), both abiotic and biotic, suggesting that it acts as a bridge between a changing environment and developmental adaptation. The abiotic stress conditions that trigger ethylene synthesis include submergence, heat, shade, exposure to heavy metals and high salt, low nutrient availability, and water deficiency 2 , 3 , 4 , 5 , 6 .

Figure 1 Overview of Ethylene Biosynthesis and Signaling Pathways in Arabidopsis and Environmental Factors That Modulate Ethylene Signaling.

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TIR1 auxin receptors are implicated in the differential response to 4-Cl-IAA and IAA in developing pea fruit

“…In the absence of pollination (or due to seed removal), ethylene evolution increases in the pericarp (Orzáez et al , 1999; Johnstone et al , 2005; Savada et al , 2017). Application of 4-Cl-IAA but not IAA to deseeded pericarps inhibits the action of ethylene (Johnstone et al , 2005).…”