Background: The plant hormone auxin is widely involved in plant growth, development, and morphogenesis, and the TIR1/AFB and AUX/IAA proteins are closely linked to rapid auxin response and signal transmission. However, their evolutionary history, historical patterns of expansion and contraction, and changes in interaction relationships are still unknown. Results: Here, we analyzed the gene duplications, interactions, and expression patterns of TIR1/AFBs and AUX/IAAs to understand their underlying mechanisms of evolution. The ratios of TIR1/AFBs to AUX/IAAs range from 4:2 in Physcomitrium patens to 6:29 in Arabidopsis thaliana and 3:16 in Fragaria vesca. Whole-genome duplication (WGD) and tandem duplication have contributed to the expansion of the AUX/IAA gene family, but numerous TIR1/AFB gene duplicates were lost after WGD. We further analyzed the expression profiles of TIR1/AFBs and AUX/IAAs in different tissue parts of Physcomitrium patens, Selaginella moellendorffii, Arabidopsis thaliana and Fragaria vesca, and found that TIR1/AFBs and AUX/IAAs were highly expressed in all tissues in P. patens, S. moellendorffii. In A. thaliana and F. vesca, TIR1/AFBs maintained the same expression pattern as the ancient plants with high expression in all tissue parts, while AUX/IAAs appeared tissue-specific expression. In F. vesca, 11 AUX/IAAs interacted with TIR1/AFBs with different interaction strengths, and the functional specificity of AUX/IAAs was related to their ability to bind TIR1/AFBs, thus promoting the development of specific higher plant organs. Verification of the interactions among TIR1/AFBs and AUX/IAAs in Marchantia polymorpha and F. vesca also showed that the regulation of AUX/IAA members by TIR1/AFBs became more refined over the course of plant evolution. Conclusions: Our results indicate that specific interactions and specific gene expression patterns both contributed to the functional diversification of TIR1/AFBs and AUX/IAAs.

Selenium (Se)-enriched tea is a well-regarded natural beverage that is often consumed for its Se supplementation benefits. However, the production of this tea, particularly in Se-abundant tea plantations, is challenging due to soil acidification. Therefore, this study aimed to investigate the effects of changes in Se under acidified soil conditions. Eight tea plantation soil monitoring sites in Southern Jiangsu were first selected. Simulated acid rain experiments and experiments with different acidification methods were designed and soil pH, as well as various Al-ion and Se-ion concentrations were systematically determined. The data were analyzed using R statistical software, and a correlation analysis was carried out. The results indicated that as the pH value dropped, exchangeable selenium (Exc-Se) and residual selenium (Res-Se) were transformed into acid-soluble selenium (Fmo-Se) and manganese oxide selenium (Om-Se). As the pH increased, exchange state aluminum (Alex) and water-soluble aluminum (Alw) decreased, Fmo-Se and Om-Se declined, and Exc-Se and Res-Se increased, a phenomenon attributed to the weakened substitution of Se ions by Al ions. In the simulated acid rain experiment, P1 compared to the control (CK), the pH value of the YJW tea plantation decreased by 0.13, Exc-Se decreased by 4 ug mg⁻¹, Res-Se decreased by 54.65 ug kg⁻¹, Fmo-Se increased by 2.78 ug mg⁻¹, and Om-Se increased by 5.94 ug mg⁻¹ while Alex increased by 28.53 mg kg⁻¹. The decrease in pH led to an increase in the content of Alex and Alw, which further resulted in the conversion of Exc-Se to Fmo-Se and Om-Se. In various acidification experiments, compared with CK, the pH value of T6 decreased by 0.23, Exc-Se content decreased by 8.35 ug kg⁻¹, Res-Se content decreased by 40.62 ug kg⁻¹, and Fmo-Se content increased by 15.52 ug kg⁻¹ while Alex increased by 33.67 mg kg⁻¹, Alw increased by 1.7 mg kg⁻¹, and Alh decreased by 573.89 mg kg⁻¹. Acidification can trigger the conversion of Exc-Se to Fmo-Se and Om-Se, while the content of available Se may decrease due to the complexation interplay between Alex and Exc-Se. This study provides a theoretical basis for solving the problem of Se-enriched in tea caused by soil acidification.

Botrytis cinerea is one of the most destructive pathogens in strawberry cultivation. Successful infection by B. cinerea requires releasing a large number of effectors that interfere with the plant’s immune system. One of the effectors required by B. cinerea for optimal virulence is the secreted protein BcXYG1, which is thought to associate with proteins near the plasma membrane of the host plant to induce necrosis. However, the host proteins that associate with BcXYG1 at the plasma membrane are currently unknown. We found that BcXYG1 binds to FvBPL4 and FvACD11 at the plasma membrane. Both FvBPL4 and FvACD11 are negative regulators of plant immunity in strawberry. Our results demonstrate that degradation of FvBPL4 by BcXYG1 promotes disease resistance while stabilization of FvACD11 by BcXYG1 suppresses the immune response. These findings suggest that BcXYG1 suppresses plant immunity and promotes B. cinerea infection by regulating FvBPL4 and FvACD11 protein levels.

The elite germplasm resources are key to the beautiful appearance and pleasant flavor of Biluochun tea. We collected and measured the agronomic traits of 95 tea plants to reveal the trait diversity and breeding value of Biluochun tea plant populations. The results revealed that the agronomic traits of Biluochun tea plant populations were diverse and had high breeding value. Additionally, we resequenced these tea plant populations to reveal genetic diversity, population structure, and selection pressure. The Biluochun tea plant populations contained two groups and were least affected by natural selection based on the results of population structure and selection pressure. More importantly, four non-synonymous single nucleotide polymorphisms (nsSNPs) and candidate genes associated with (−)-gallocatechin gallate (GCG), (−)-gallocatechin (GC), and caffeine (CAF) were detected using at least two GWAS models. The results will promote the development and application of molecular markers and the utilization of elite germplasm from Biluochun populations.

Soil acidification in tea (Camellia sinensis L.) gardens leads to nutrient depletion, inhibits the growth of tea plants, reduces tea quality, and activates heavy metals such as cadmium (Cd) in the soil. To clarify the impact of soil pH under acidified conditions on tea plant growth physiology and the key genes involved in Cd²⁺ transport in tea plants, this study planted ‘Longjing 43’ under different pH levels (4.0, 4.5, and 5.5) and Cd concentrations (T1 = 0 mg L⁻¹, T2 = 0.01 mg L⁻¹, T3 = 0.05 mg L⁻¹, and T4 = 0.2 mg L⁻¹). The results showed that the concentration of Cd in tea plants from highest to lowest was root > stem > mature leaves > young leaves. Under T4, with decreasing pH, the total chlorophyll significantly decreased, the Fv/Fm significantly decreased, stomatal aperture reduced, and net photosynthetic rate and transpiration rate significantly decreased. In the T4 treatment at pH = 4.0, the contents of free proline and malondialdehyde were both the highest, while superoxide dismutase (SOD), peroxidase (POD), and catalase from micrococcus lysodeiktic (CAT) showed a significant negative correlation with pH. By screening the tea genome data, a total of nine CsHMAs involved in metal ion transport were identified. The qRT-PCR results indicated that the expression level of CsHMA2 was the highest in young leaves of tea, and CsHMA2 was localized on the cell membrane. Under T4 and pH = 4.0, transient overexpression of CsHMA2 enhanced the ability of tea to transport Cd²⁺, whereas transient silencing of CsHMA2 weakened this ability. These findings not only help understand how tea adapts and regulates its physiological processes in acidic environments but also provide an important theoretical basis and technical guidance for soil improvement in tea gardens, the control of heavy metal pollution, and the optimization of tea quality.

Precision soil management is fundamental to the sustainable production of high-quality tea, yet the spatial integration of fertility and heavy metal safety remains a significant challenge. This study aimed to delineate multi-dimensional management zones (MZs) in the tea plantations of Tianmuhu, Jiangsu Province, by evaluating three clustering algorithms: K-means (KM), Fuzzy C-means (FCM), and Iterative Self-Organizing Data Analysis Technique (ISODATA). A total of 70 representative soil samples were analyzed for 10 properties. Descriptive statistics revealed pronounced spatial heterogeneity, particularly for Hg (CV = 71.04%) and P (CV = 61.83%). Pearson correlation and Principal Component Analysis (PCA) demonstrated strong synergistic relationships among organic matter (OM), nitrogen (N), and potassium (K) (r = 0.49–0.69, p < 0.01), which formed a distinct Fertility Factor on PC1. Conversely, PCA identified divergent sources for heavy metals, with Cr primarily governed by pedogenic processes (PC2), while Cd were associated with anthropogenic inputs. Guided by these distinct spatial drivers, this study separately delineated fertility and heavy metal safety MZs. The optimal number of clusters was determined by balancing statistical validity with spatial operationality via the Silhouette Coefficient (SC) and Smoothness Index (SI), with results indicating that a 2–3 zone scheme yielded the most favorable scores. Comparative analysis showed that for soil fertility, ISODATA outperformed KM and FCM by effectively capturing the high variability of P and producing statistically distinct zones (p < 0.05). For heavy metal pollution, FCM provided better partitioning by reflecting the continuous gradients of composite contaminants. Validation results showed that while 61% of the area was classified as high-fertility (ISODATA), approximately 63–75% fell into relatively higher heavy metal accumulation categories. This dual-objective zoning framework provides a scientific basis for site-specific fertilization and targeted environmental monitoring in the regional tea industry.