Department of Plant Pathology, Faculty of Agriculture, Tarbiat Modares University, Tehran PO Box 14115-336, Iran.
Department of Plant Protection, Faculty of Agriculture, University of Jiroft, Jiroft PO Box 7867161167, Iran.
Tree Physiol. 2024 Sep 3;44(9). doi: 10.1093/treephys/tpae097.
Using integrated pest management without relying on chemical pesticides is one of the most attractive approaches to controlling plant pathogens. Among them, using resistant cultivars or rootstocks against diseases in combination with beneficial microorganisms has attracted special attention. The citrus nematode is one of the major constraints of citrus cultivation worldwide. We showed that the mycorrhizal arbuscular fungus, Funneliformis mosseae, increased growth parameters including shoot and root length and biomass of two main rootstocks of citrus, sour orange and Volkamer lemon, in noninfected and infected plants with citrus nematode. It decreased the infection rate by citrus nematode in both rootstocks compared with nonmycorrhizal plants. The rate of decrease in nematode infection was highest when plants were pre-inoculated with F. mosseae and was lowest when nematode was inoculated before F. mosseae. However, when nematode was inoculated before the fungus, the fungus was still able to mitigate the negative effect of infection by nematode compared with plants inoculated with nematode only. This suggests that the timing of inoculation plays a crucial role in the effectiveness of F. mosseae in reducing nematode infection. Moreover, monitoring of the expression of two genes, phenylalanine ammonia-lyase and β-1,3-glucanase, which are involved in systemic-acquired resistance (SAR) showed that although they were significantly upregulated in mycorrhizal plants compared with nonmycorrhizal plants, they showed the highest expression when plants were pretreated with fungus before nematode inoculation, thus, indicating that plants were primed. In summary, F. mosseae primes the defense-related genes involved in SAR, increasing plant defensive capacity and boosting growth parameters in citrus rootstock. This has important implications for the agricultural industry.
利用不依赖化学农药的综合虫害管理是控制植物病原体的最具吸引力的方法之一。其中，利用抗性品种或砧木结合有益微生物的方法引起了特别关注。柑橘线虫是全球柑橘种植的主要限制因素之一。我们表明，菌根丛枝菌根真菌摩西管柄囊霉（Funneliformis mosseae）增加了两个主要柑橘砧木——酸橙和沃克勒柠檬的生长参数，包括茎和根的长度以及生物量，无论是在感染柑橘线虫的植物还是未感染的植物中都是如此。与非菌根植物相比，它降低了两种砧木中柑橘线虫的感染率。与仅接种线虫的植物相比，当植物预先接种摩西管柄囊霉时，线虫感染率下降幅度最大，而当线虫先接种摩西管柄囊霉时，线虫感染率下降幅度最小。然而，当线虫先接种真菌时，真菌仍然能够减轻线虫感染的负面影响，使其与仅接种线虫的植物相比。这表明接种时间在摩西管柄囊霉降低线虫感染的有效性方面起着至关重要的作用。此外，监测参与系统获得性抗性（SAR）的两个基因——苯丙氨酸解氨酶和β-1,3-葡聚糖酶的表达表明，尽管与非菌根植物相比，菌根植物中的这两个基因表达显著上调，但当植物在接种线虫之前用真菌预处理时，它们的表达最高，因此表明植物已被启动。总之，摩西管柄囊霉启动了与 SAR 相关的防御基因，提高了柑橘砧木的防御能力，并促进了其生长参数的提高。这对农业产业具有重要意义。
