The rhizospheric microbial community is one of the major environmental factors affecting the distribution and fitness of plants. Ancient wild tea plants are rare genetic resource distributed in Southwest China. In this study, we investigated that rhizospheric bacterial communities of ancient wild tea plants along the elevational gradients (2050, 2200, 2350 and 2500 m) in QianJiaZhai Reserve of Ailao Mountains. According to the Illumina MiSeq sequencing of 16 S rRNA gene amplicons,Proteobacteria,AcidobacteriaandActinobacteriawere the dominant phyla with the relative abundance 43.12%, 21.61% and 14.84%, respectively. TheVariibacterwas the most dominant genus in rhizosphere of ancient wild tea plant. Phylogenetic null modeling analysis suggested that rhizospheric bacterial communities of ancient wild tea plants were more phylogenetically clustered than expected by chance. The bacterial community at 2050 m was unique with the highest alpha diversity, tend to cluster the nearest taxon and simple co-occurrence network structure. The unique bacterial community was correlated to multiple soil factors, and the content soil ammonium nitrogen (NH₄⁺-N) was the key factor affecting the diversity and distribution of bacterial community along the elevational gradients. This study provided the necessary basic information for the protection of ancient tea trees and cultivation of tea plants.

In this study, the genetic diversity and population structure of 4 wild ancient tea tree (Camellia taliensis) populations at different altitudes (2,050, 2,200, 2,350, and 2,500 m) in Qianjiazhai Nature Reserve, Zhenyuan country, Yunnan province, were investigated using EST-SSR molecular markers to compare their genetic variation against altitude. In total, 182 alleles were detected across all loci, ranging from 6 to 25. The top one informative SSR was CsEMS4 with polymorphism information content (PIC) of 0.96. The genetic diversity of this species was high, with 100% of loci being polymorphic, an average Nei’s gene diversity (H) of 0.82, and Shannon’s information index (I) of 1.99. By contrast, at the population level, the genetic diversity of wild ancient tea tree was relatively low, with values of H and I being 0.79 and 1.84, respectively. Analysis of molecular variance (AMOVA) revealed a minor genetic differentiation (12.84%) among populations, and most of the genetic variation (87.16%) was detected within populations. Using population structure analysis, we found that the germplasm of wild ancient tea tree was divided into three groups, and there was a substantial gene exchange among these three groups at different altitudes. Divergent habitats caused by altitudes and high gene flow played important roles in genetic diversity of wild ancient tea tree populations, which will provide new opportunities for promoting their protection and potential utilization.

Potentially toxic elements (PTEs) pollution occurs widely in soils due to various anthropogenic activities. Lead (Pb) and cadmium (Cd) coexist in soil frequently, threatening plant growth. To explore the interaction effect between Pb and Cd in Ficus parvifolia and the response of plant physiological characteristics to Pb and Cd stress, we designed a soil culture experiment. The experiment demonstrated that Pb stress improved leaf photosynthesis ability, while Cd stress inhibited it. Furthermore, Pb or Cd stress increased malonaldehyde (MDA) content, but plants were able to reduce it by increasing antioxidant enzyme activities. The presence of Pb could alleviate Cd phytotoxicity in plants by inhibiting Cd uptake and accumulation as well as increasing leaf photosynthesis and antioxidant ability. Pearson correlation analysis illustrated that the variability of Cd uptake and accumulation between Pb and Cd stress was related to plant biomass and antioxidant enzyme activities. This research will offer a new perspective on alleviating Cd phytotoxicity in plants.

The market value of tea is largely dependent on the tea species and cultivar. Therefore, it is important to develop efficient molecular markers covering the entire tea genome that can be used for the identification of tea varieties, marker-assisted breeding, and mapping important quantitative trait loci for beneficial traits. In this study, genome-wide molecular markers based on intron length polymorphism (ILP) were developed for tea trees. A total of 479, 1393, and 1342 tea ILP markers were identified using the PCR method in silico from the ‘Shuchazao’ scaffold genome, the chromosome-level genome of ‘Longjing 43’, and the ancient tea DASZ chromosome-level genome, respectively. A total of 230 tea ILP markers were used to amplify six tea tree species. Among these, 213 pairs of primers successfully characterize products in all six species, with 112 primer pairs exhibiting polymorphism. The polymorphism rate of primer pairs increased with the improvement in reference genome assembly quality level. The cross-species transferability analysis of 35 primer pairs of tea ILP markers showed an average amplification rate of 85.17% through 11 species in 6 families, with high transferability in Camellia reticulata and tobacco. We also used 40 pairs of tea ILP primers to evaluate the genetic diversity and population structure of C. tetracocca with 176 plants from Puan County, Guizhou Province, China. These genome-wide markers will be a valuable resource for genetic diversity analysis, marker-assisted breeding, and variety identification in tea, providing important information for the tea industry.

Cold stress causes considerable damage to tender tea seedlings. Previous studies have explored changes in the physiological and biochemical factors of tea in response to cold stress; however, the mechanisms of cold resistance in ancient tea tree plants are unclear. The aim of this study was to analyze the effects of 0 °C cold stress for 15 days and 24 °C ambient temperature recovery for 5 days on the physiological and biochemical characteristics of two representative old tea varieties: Dali tea and Siqiu tea. The results revealed significant changes in antioxidant, photosynthetic efficiency, and physiological and biochemical indicators in response to cold stress, with the two species exhibiting different patterns. Cold stress decreased chlorophyll and carotene content, F_v/F_m, Y_(II), non-photochemical quenching coefficient, photochemical quenching, and superoxide dismutase (SOD) activity, and increased intercellular CO₂ concentration and ascorbate peroxidase activity. Siqiu tea showed a higher increase in soluble sugar content and antioxidant enzyme activity and a lower accumulation of malondialdehyde and minimal fluorescence (F₀) than Dali, indicating a greater tolerance to cold stress. Based on partial least-squares discriminant analysis, six key differential physiological indicators of cold resistance—water-soluble sugar, F₀, peroxidase, catalase, SOD, and gas conductance—were identified. Our findings provide technical support for identifying ways to protect ancient tea trees from extreme weather conditions.

Tea (Camellia sinensis L.), an important economic crop in China, is highly favored by the population. Microorganisms can help plants acquire soil nutrients and cope with various stresses, and the diversity and structural composition of the rhizosphere microbial community of tea plants are crucial for ensuring the growth and quality of tea leaves. Therefore, we studied the differences in soil nutrients, enzyme activities and microbial communities between two different tea gardens (a tableland tea garden and an ancient tea plantation) in different ecological niches (rhizosphere and bulk soil), as well as the impacts they experienced. The results show that the soil pH levels in the ancient tea plantation were within the optimal range (4.5–5.5), and both rhizosphere and bulk soil nutrients in the ancient tea plantation were higher than those in the tableland tea garden, except for TP; the nutrients in the rhizospheres of ancient tea trees were more abundant. Moreover, higher enzyme activities were observed in the rhizosphere soil than those in the bulk soil in both tea gardens, and both the tableland and ancient tea garden soils were subjected to a certain degree of C&N limitations. The microbial communities of the two tea gardens were dominated by bacteria, but the α-diversity of the bacterial and fungal communities in the rhizosphere soil of the tableland tea garden was higher than that in the ancient tea plantation. The bacterial communities were largely dominated by Proteobacteria and Acidobacteriota, and the fungal communities were largely dominated by Ascomycota and Basidiomycota in the two tea gardens. The structure and composition of soil bacterial communities in the two tea gardens were similar, whereas significant differences were observed in the fungal communities. In addition, soil pH and SWC were the key factors influencing the fungal community in both the rhizosphere and bulk soil in the two tea gardens, whereas the bacterial community was more significantly affected by soil TN, NH₄⁺-N, SWC and DON. These findings provide essential foundational information for the preservation of ancient tea plantations, the ecological adaptability of ancient tea trees and the management of tableland tea gardens.