Light plays an essential role in the outcome of plant-pathogen interactions. In this study, the effect of pre- and post-inoculation light quality on Botrytis cinerea disease development in strawberry leaves was investigated. Circadian variations in leaf susceptibility to Botrytis cinerea were tested by inoculating at 5 h, 12 h, or 16 h after the start of photoperiod. The effects of 4 h and/or 12 h of red or blue light combined with white light in a 16 h photoperiod on leaf susceptibility and metabolites were studied. Light presence significantly decreased leaf susceptibility to Botrytis irrespective of light quality. Leaf susceptibility to B. cinerea showed significant circadian variations. Susceptibility was highest in leaves inoculated 12 h after the start of photoperiod followed by incubation in the dark. When disease development took place under the light regime, the shorter the light period after inoculation the stronger the disease symptoms. Twelve hours of red light radiation in a 16 h photoperiod increased, while 12 h blue light radiation decreased leaf resistance, resulting in alterations in the circadian variation of leaf susceptibility. These alterations correlated with changes in leaf metabolites, such as hydrogen peroxide, total phenolics and hexoses. Overall, we conclude that twelve hours of red light followed by white light in a 16 h photoperiod efficiently increased leaf resistance to B. cinerea.

光在植物-病原体相互作用的结果中起着至关重要的作用。在这项研究中，研究了接种前和接种后光质对草莓叶片灰葡萄孢病发展的影响。通过在光周期开始后5小时，12小时或16小时接种来测试叶片对灰葡萄孢的敏感性的昼夜变化。研究了在16 h光周期中4 h和/或12 h红光或蓝光与白光结合对叶片敏感性和代谢产物的影响。无论光照质量如何，光照的存在都会显着降低叶片对葡萄孢的敏感性。叶片对灰葡萄孢的敏感性显示显着的昼夜节律变化。在光周期开始后12小时接种，然后在黑暗中孵育的叶片中，敏感性最高。当在光照条件下发生疾病发展时，接种后光照时间越短，疾病症状就越强。在16小时的光周期中，十二个小时的红光辐射增加，而十二小时的蓝光辐射则降低叶片抗性，导致叶片敏感性的昼夜节律变化发生变化。这些变化与叶片代谢产物的变化相关，例如过氧化氢，总酚和己糖。总的来说，我们得出的结论是，在16小时的光周期中，十二个小时的红光继之以白光可以有效地提高叶片对灰葡萄孢的抵抗力。