Arbuscular mycorrhizal fungus alleviates anthracnose disease in tea seedlings

Abstract

Tea has been gaining increasing popularity all over the world in recent years, and its yield and quality depend on the growth and development of tea plants [Camellia sinensis (L.) Kuntze] in various environments. Nowadays, biotic stress and extreme weather, such as high temperature, drought, waterlogging, pests, and diseases, bring about much pressure on the production of tea with high quality. Wherein anthracnose, which is the most common and serious disease of tea plants, has earned more and more attention, as its control mainly relies on chemical pesticides. Arbuscular mycorrhizal fungi (AMF), forming symbiosis with most terrestrial plants, participate in plant resistance against the anthracnose disease, which was found by previous studies in a few herbaceous plants. However, there are a few studies about arbuscular mycorrhizal (AM) fungal regulation of the resistance to the anthracnose pathogen in woody plants so far. In this paper, we investigated the effect of AMF on the development of anthracnose caused by Colletotrichum camelliae and tried to decipher the pertinent mechanism through transcriptome analysis. Results showed that inoculating AMF significantly reduced the damage of anthracnose on tea seedlings by reducing the lesion area by 35.29% compared to that of the control. The content of superoxide anion and activities of catalase and peroxidase significantly increased (P < 0.05) in mycorrhizal treatment in response to the pathogen with 1.23, 2.00, and 1.39 times higher, respectively, than those in the control. Pathways of plant hormone signal transduction, mitogen-activated protein kinase (MAPK) signaling, and phenylpropanoid biosynthesis might play roles in this regulation according to the transcriptomic results. Further redundancy analysis (RDA) and partial least squares structural equation modeling (PLS-SEM) analysis found that plant hormones, such as auxin and ethylene, and the antioxidant system (especially peroxidase) were of great importance in the AM fungal alleviation of anthracnose. Our results preliminarily indicated the mechanisms of enhanced resistance in mycorrhizal tea seedlings to the anthracnose pathogen and provided a theoretical foundation for the application of AMF as one of the biological control methods in tea plantations.

Insight into regulation of adventitious root formation by arbuscular mycorrhizal fungus and exogenous auxin in tea plant (Camellia sinensis L.) cuttings

“…It was found that these mycorrhizal colonization related genes, RAM2 ( LOC114297081 ), STR ( LOC114323273 ) and STR2 ( LOC114276941 ), were only significantly up-regulated in the cuttings at the S2 stage ( Supplementary Data 1 ) compared with the control in the second experiment of this study. And it was supposed that ARs have started to establish mycorrhizal symbiosis with AMF, which is consistent with our previous observations in the roots of mycorrhizalized tea seedlings ( Chen et al., 2023 ). All these results could indicate that the presence of AMF in the cutting substrate or root of cuttings, making it possible to further analyze how AMF affects the rooting of tea cuttings.…”

“…We speculated that this may be related to the effect of exogenous auxin on the symbiosis establishment between AMF and root. In the first experiment, IBA treatment significantly promoted the infection of AMF on the roots of ‘Pingyangtezao’ cuttings (46.29%, Table 2 ), which was higher than our previous mycorrhizal experiments on tea plant ( Chen et al., 2021 ; Chen et al., 2023 ). Same results were also found in the other two varieties, but did not reach a significant level.…”

“…To conduct quantitative real-time PCR (qRT-PCR), another aliquot of extracted RNA was used according to the former established protocol ( Chen et al., 2023 ). In tea plants, 18s rRNA ( AB120309.1 ) was chosen as the reference gene for qRT-PCR analysis as reported by Wei et al.…”

“…Arbuscular mycorrhizal fungus (AMF), forming symbiosis with almost 80% of terrestrial plants, can exert both directly and indirectly growth promotion effect in normal or abnormal conditions and elevate the resistance to diseases and pests ( Du et al., 2022 ; Eck et al., 2022 ). In our previous research, we found that inoculating with AMF significantly increased the resistance to anthracnose in tea seedlings through the regulation of plant hormones and the antioxidant system (especially peroxidase) ( Chen et al., 2023 ). Because tea plants are mycorrhizal-dependent plants ( Liu et al., 2023a ), AMF plays a great role in many aspects.…”

Colonization of root endophytic fungus Serendipita indica improves drought tolerance of Pinus taeda seedlings by regulating metabolome and proteome

“…Symbiosis between plants and microorganisms occurs wide in natural ecosystems, affects plant terrestrializations (Puginier et al, 2022), evolution (Batstone, 2022;van Galen et al, 2023), and tolerance to abiotic and biotic stress (Zeng et al, 2022), and widens the habitability ranges of plants (Muñoz and Carneiro, 2022). Among all the beneficial microorganisms symbiosing with plants, five families of microorganisms have been greatly paid on attentions, i.e., arbuscular mycorrhizal fungi (Kaur et al, 2022;Razak and Gange, 2023;Chen W. et al, 2023), ectomycorrhizal fungi (Karlsen-Ayala et al, 2022;Jörgensen et al, 2023;Xiao et al, 2023), root endophytic fungi (Manzur et al, 2022;Sun et al, 2022;Qin et al, 2023), dark septate fungi (Gaber et al, 2023;Wang et al, 2023;Chen S. et al, 2023), and plant growth-promoting rhizobacteria (PGPR) (Ahmad et al, 2022;Gowtham et al, 2022;Zhao et al, 2023). These beneficial microorganisms show strong effects on their plant hosts under drought stress (Ahmad et al, 2022;Gowtham et al, 2022;Zhao et al, 2023).…”