Journal of Tea Science Research, 2024, Vol.14, No.1, 10-18 http://hortherbpublisher.com/index.php/jtsr 13 These viruses are spread by means of vector insects or root contact, causing damage and yellowing of tea tissue. The incidence of tea yellowing is also related to the resistance and immune mechanism of tea plant itself (Jin et al., 2021). The resistance of tea cultivars to tea yellowing disease is different, and some cultivars have strong resistance to virus infection. At the same time, the immune mechanism of tea plant plays an important role in resisting pathogen invasion, including activation of antioxidant system and synthesis of antibacterial substances. 2.2 Influence of tea yellowing on tea growth and quality Tea yellowing has a significant effect on the growth and quality of tea. Tea yellowing can lead to growth restriction of tea plants. Virus infection and tissue yellowing will destroy the photosynthesis of tea trees and reduce the photosynthetic efficiency of leaves, thus affecting the growth and development of plants. After tea tree is attacked by tea yellowing disease, the number and size of leaves are reduced, and the growth rate is slowed down, resulting in poor overall growth state of tea tree. Tea yellowing disease will reduce the quality of tea, and there are obvious differences in color, aroma and taste between yellow tea and healthy tea. Tea yellowing causes the leaves to lose their green pigment, making the tea lighter in color and losing its vibrant green color. At the same time, the metabolic activity of the diseased tissue is reduced, resulting in the aroma and taste of the tea being affected (Jin et al., 2021). Tea yellowing may also cause the accumulation of harmful substances in tea and affect the flavor and quality of tea. Tea yellowing also affects the yield stability of tea plants. Tea yellowing causes poor growth of tea plants and reduces the yield of leaves, thus reducing the yield stability of tea. This is an important economic loss for the tea growing industry. The pathogenesis of tea yellowing involves many factors, including environmental factors, pathogen infection, resistance and immune mechanism of tea plant itself. Tea yellowing has a significant impact on the growth and quality of tea, including tea tree growth restriction, tea quality reduction and yield stability decline. In-depth research on tea yellowing disease is helpful to formulate effective prevention and control strategies to ensure the sustainable development of tea industry. 3 Interaction between Tea Root Probiotics and Tea Yellowing 3.1 Study on the prevention and control effect of probiotics on tea yellowing disease Tea root probiotics play an important role in the prevention and treatment of tea yellowing disease. The study on the effect of probiotics on tea yellowing can provide an effective disease management strategy for tea industry. Liu et al. (2021) screened a series of probiotic strains with disease resistance characteristics, and isolated several probiotic strains with antagonistic ability against pathogens from the rhizosphere of tea tree through screening and identification under laboratory conditions. These strains can inhibit the growth and spread of pathogenic bacteria of tea yellowing disease, so as to reduce the degree of disease of tea trees. Yu et al. (2020) conducted a field test of probiotics, selecting areas with severe tea yellows in tea gardens, and applying the selected probiotics to the roots of tea trees. The effect of probiotics on tea yellowing was evaluated by comparing experimental group and control group. The results showed that the degree of yellowing of tea leaves was significantly reduced, the growth state of tea plants was significantly improved, and the tea yield and quality were also improved. 3.2 Effects of probiotics on rhizosphere microbial community structure of tea tree The application of probiotics can not only directly affect the control effect of tea yellowing disease, but also may be achieved by regulating the rhizosphere microbial community structure of tea tree (Figure 2). Tea rhizosphere microbial community is a complex ecosystem in which microbial interactions have an important impact on plant health and disease development (Liu et al., 2021).
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