Cycas panzhihuaensis inhabits regions where summer temperatures can exceed 40 degrees C, and these extreme conditions may intensify with ongoing global warming. However, how this species adapts to such thermal extremes is not well understood. To investigate the responses of C. panzhihuaensis to heat stress, some physiological characteristics along with lipid and fatty acid profiles were analyzed. The results show that heat stress induced soil water loss but did not cause leaf water loss and visible symptoms of leaf damage. However, photoinhibition was induced and heat dissipation was inhibited under the stress. In the recovered plants, both heat dissipation and maximum photochemical efficiency exhibited significant increases compared to the stressed plants but did not return to the control level. Most lipid categories including phospholipids and saccharolipids accumulated significantly following both the stress and subsequent recovery. However, the content of total neutral glycerolipids maintained unchanged after various treatments. The ratio of phosphatidylcholine/phosphatidylethanolamine decreased significantly and the ratios of both digalactosyldiacylglycerol/monogalactosyldiacylglycerol and triacylglycerol/diacylglycerol increased significantly in the stressed plants. Compared to the control plants, the relative content of polyunsaturated fatty acids significantly increased, while that of both saturated and monounsaturated fatty acids significantly declined in both stressed and recovered plants. Under stress conditions, the unsaturation levels of total neutral glycerolipids and their constituent components significantly increased, whereas those of phosphatidylglycerol and total saccharolipids exhibited a marked decrease. In conclusion, C. panzhihuaensis can tolerate extremely high temperatures to some extent which might be associated with the adjustments in lipid composition and unsaturation levels.

Silverleaf whitefly, Bemisia tabaci (Hemiptera: Aleyrodidae), is a destructive insect pest damaging to diverse crops by vectoring several plant pathogenic viruses, which consequently causes economic losses in crop production. As the resistance of whiteflies to chemical insecticides is increasing, this study aimed to investigate the potential of entomopathogenic fungi as an alternative. A total of 72 entomopathogenic fungal isolates, collected from soils using Tenebrio molitor larvae as an insect baiting method, were assessed for their virulence against 2nd nymphs of whitefly. Their virulence was assayed by dipping whitefly-infested tomato leaves in fungal conidia suspensions at 1.0 x 107 conidia/mL. Among the tested isolates, two isolates of Beauveria bassiana JEF-462 and JEF-507 showed high virulence. In the assessment of virulence depending on conidia concentrations, the estimated LC50 values for JEF-462 and JEF-507 were similarly 8.7-14.0 x 107 conidia/mL. However, B. bassiana JEF-507 showed higher conidial productivity and thermotolerance on most of tested 12 grain substrates than B. bassiana JEF-462, and millet was the most suitable grain substrate. Additionally, siloxane as a surfactant was able to sufficiently exhibit the insecticidal activity of JEF-507 against whitefly nymphs compared with other surfactants. In a pot-based greenhouse trial, JEF-507 showed higher control efficacy than chemical insecticides, dinotefuran and spinetoram. This work suggests that B. bassiana JEF-507 could be competitively used as a biopesticide to control silverleaf whiteflies while overcoming current resistance issues. The JEF-507 isolate has been registered in Korea, 2022 and successfully commercialised as the name of Chongchae-Stop in this local market to control whitefly and thrips.