Myo-inositol phosphate synthase improves heat stress tolerance by ethylene-mediated modulation of chlorophyll content and photosynthetic efficiency.

L-myo-inositol phosphate synthase (MIPS; EC 5.5.1.4) encodes the enzyme synthesizing Myo-inositol for plant growth and development. Myo-inositol and its phosphate derivatives are involved in various physiological functions ranging from cell wall synthesis, chromatin remodeling, signal transduction, and providing stress responses. In the present study, we report that MIPS regulates chlorophyll content and photosynthesis efficiency via the ethylene signaling pathway. We have used Triticum aestivum MIPS-A (TAMIPS-A) for the present study and characterized it by mutant complementation and overexpression studies in Arabidopsis. TaMIPS-A overexpressing Arabidopsis transgenics were analyzed physiologically under thermal stress conditions. Analysis of overexpression TaMIPS-A transgenics under control and thermal stress conditions revealed them to have enhanced photosynthetic potential under heat stress. When TaMIPS-A overexpression (OE) Arabidopsis transgenics are supplemented with either ACC, the ethylene precursor, or AgNO3, the ethylene signaling inhibitor indicated that MIPS regulates the photosynthetic efficiency and chlorophyll content via the ethylene signaling pathway under control and thermal stress. Expression analysis of essential genes involved in the ethylene biosynthetic and signaling pathway corroborated.

Antrodia cinnamomea Extraction Waste Supplementation Promotes Thermal Stress Tolerance and Tissue Regeneration Ability of Zebrafish.

Antrodia cinnamomea (AC) has been shown to have anti-inflammatory, anti-tumor, and immunomodulation activities. It is estimated that hundreds of metric tons of AC extraction waste (ACEW) are produced per year in Taiwan. This study aims to assess the feasibility of applying ACEW as feed supplement in the aquaculture industry. ACEW significantly inhibited the growth of microorganisms in the water tank, by around 39.4% reduction on the fifth day with feed supplemented of 10% ACEW. The feed conversion efficiency of zebrafish with 10% ACEW supplementation for 30 days was 1.22-fold compared to that of the control. ACEW dramatically improved the tolerances of zebrafish under the heat and cold stresses. When at water temperature extremes of 38 °C or 11 °C, compared to the 100% mortality rate in the control group, the 10% ACEW diet group still had 91.7% and 83.3% survival rates, respectively. In a caudal fin amputation test, the fin recovery of zebrafish was increased from 68.4% to 93% with 10% ACEW diet after 3-week regeneration. ACEW effectively down-regulated the gene expression of TNF-α, IL-1ß, IL-6, and IL-10, and up-regulated the gene expression of IL-4/13A. Additionally, the supplement of ACEW in the feed can maintain and prevent the fish's body weight from dropping too much under enteritis. Taken together, ACEW has beneficial potential in aquaculture.