Ahmad Imtiaz, Jimenez-Gasco Maria Del Mar, Barbercheck Mary E
Department of Entomology, The Pennsylvania State University, University Park, PA 16802, USA.
Department of Plant Pathology and Environmental Microbiology, The Pennsylvania State University, University Park, PA 16802, USA.
Pathogens. 2024 Jun 27;13(7):544. doi: 10.3390/pathogens13070544.
Plants face many environmental challenges and have evolved different strategies to defend against stress. One strategy is the establishment of mutualistic associations with endophytic microorganisms which contribute to plant defense and promote plant growth. The fungal entomopathogen is also an endophyte that can provide plant-protective and growth-promoting benefits to the host plant. We conducted a greenhouse experiment in which we imposed stress from deficit and excess soil moisture and feeding by larval black cutworm (BCW), , to maize plants that were either inoculated or not inoculated with (Mr). We evaluated plant growth and defense indicators to determine the effects of the interaction between Mr, maize, BCW feeding, and water stress. There was a significant effect of water treatment, but no effect of Mr treatment, on plant chlorophyl, height, and dry biomass. There was no effect of water or Mr treatment on damage caused by BCW feeding. There was a significant effect of water treatment, but not Mr treatment, on the expression of bx7 and rip2 genes and on foliar content of abscisic acid (ABA), 2,4-dihydroxy-7-methoxy-1,4-benzoxazin-3-one (DIMBOA), and gibberellin 19 (GA19), whereas GA53 was modulated by Mr treatment. Foliar content of GA19 and cis-Zeatin (cZ) was modulated by BCW feeding. In a redundancy analysis, plant phenology, plant nutrient content, and foliar DIMBOA and ABA content were most closely associated with water treatments. This study contributes toward understanding the sophisticated stress response signaling and endophytic mutualisms in crops.
植物面临许多环境挑战，并进化出不同的策略来抵御压力。一种策略是与内生微生物建立互利共生关系，这些微生物有助于植物防御并促进植物生长。真菌昆虫病原体也是一种内生菌，可为宿主植物提供植物保护和促进生长的益处。我们进行了一项温室实验，对接种或未接种Mr的玉米植株施加土壤水分亏缺和过剩以及幼虫小地老虎（BCW）取食造成的压力。我们评估了植物生长和防御指标，以确定Mr、玉米、BCW取食和水分胁迫之间相互作用的影响。水分处理对植物叶绿素、高度和干生物量有显著影响，但Mr处理没有影响。水分或Mr处理对BCW取食造成的损害没有影响。水分处理对bx7和rip2基因的表达以及脱落酸（ABA）、2,4-二羟基-7-甲氧基-1,4-苯并恶嗪-3-酮（DIMBOA）和赤霉素19（GA19）的叶片含量有显著影响，但Mr处理没有影响，而GA53受Mr处理调节。GA19和顺式玉米素（cZ）的叶片含量受BCW取食调节。在冗余分析中，植物物候、植物养分含量以及叶片DIMBOA和ABA含量与水分处理关系最为密切。这项研究有助于理解作物中复杂的应激反应信号和内生共生关系。
