Plants are prone to low inorganic phosphorus (Pi) abiotic stress, which has adverse effects on the growth, development and physiological metabolic processes. Camellia hainanica, a local variety in Hainan, mostly grows in low-phosphorus environments. C. hainanica has unique genetic characteristics that distinguish it from C. oleifera. In this study, a tropical cultivar Haida Oil-tea 4 (H4) was used as the research object to screen reference genes suitable for quantitative real-time polymerase chain reaction (qRT-PCR) analysis of C. hainanica under low Pi stress. The expression levels of six candidate reference genes, EF1α1, GAPDH, Actin, UBQ, ETIF3H and TUB2, were detected by qRT-PCR. The stability of each reference gene was comprehensively evaluated using ΔCt, geNorm, NormFinder, BestKeeper software and RefFinder online analysis tools, and ETIF3H was identified as the optimal reference gene. Using ETIF3H as the reference gene, we validated the expression levels of three low Pi responsive genes. The results showed that the target genes were differentially expressed in response to low Pi, indicating that ETIF3H is suitable as a reference gene for detecting gene differential expression under low Pi stress conditions. This work would provide appropriate reference genes for transcript normalization in H4 under low Pi stress, which will facilitate subsequent study of phosphorus signal-response gene expression in C. hainanica.

To address the limitation of conventional rubber plantation suitability assessments that overlook geographical environmental heterogeneity, this study proposes a suitability evaluation approach based on geographical zoning modeling. Eight key indicators were selected from three dimensions, topographic conditions, hydrothermal conditions, and cold damage risk, to construct the evaluation index system. The weight of these indicators was determined by integrating the Analytic Hierarchy Process (AHP) with the GeoDetector method. Using the Ailao Mountains ridge as a geographical demarcation, the rubber plantation area in Yunnan province was divided into western and eastern zones, for which region-specific factor suitability grading standards were established and applied for factor reclassification. Subsequently, the reclassified factors were integrated through linear weighting to produce a comprehensive suitability evaluation, classifying the results into four categories, unsuitable, marginally suitable, moderately suitable, and highly suitable. Among the six prefecture-level regions engaged in rubber cultivation, highly suitable areas accounted for approximately 4.29% of the total land area, moderately suitable areas for 2.79%, and marginally suitable areas for 5.06%, totaling about 12.14%. These areas are mainly concentrated in Xishuangbanna, Pu'er and Honghe. Overlay analysis with 2024 rubber plantation distribution data revealed that about 47.80% of existing plantations in highly suitable zones, 22.09% in moderately suitable zones, and 19.29% in marginally suitable zones, accounting for a combined 89.18%. This distribution shows a high degree of spatial consistency with the actual planting patterns. The evaluation results, with a spatial resolution of 10 m, are capable of reflecting fine-scale variations in Yunnan's mountainous environments, and can thus provide valuable references for rubber plantation planning and adjustment in Yunnan province.

The glyoxalase system, comprising glyoxalase I (GLYI) and glyoxalase II (GLYⅡ), serves as a key mechanism for detoxifying excess methylglyoxal (MG) in plants and plays an important role in responses to abiotic stress and pathogen infection. To date, genome-wide identification and expression analysis of GLY gene family have not been reported in sugarcane. In this study, we identified 50 SsGLYI genes and 52 SsGLYⅡ genes from the wild sugarcane Saccharum spontaneum, and systematically analyzed the physicochemical properties, gene structures, promoter cis-acting elements, and expression patterns. SsGLY genes were randomly distributed across 30 chromosomes. All 43 SsGLYI members contained a conserved Motif1 (PF00903), while all SsGLYII proteins possessed a conserved Motif1 (PF00753). A total of 39 SsGLYI proteins contained four metal-binding sites (H/Q, L, H, E), except SsGLYII8.1-8.4 from subfamily IV, which were Zn²⁺-dependent, the remaining SsGLYI proteins were Ni²⁺-dependent. Only 26 SsGLYI proteins contained both the THxHxDH metal-binding domain and the C/GHT active site. Collinearity analysis identified 41 pairs of collinear genes, among which 39 pairs had Ka/Ks values less than 1, indicating that the SsGLY gene family has undergone predominant purifying selection during evolution. The expression levels of SsGLYI subfamily V and SsGLYⅡ subfamily Ⅲ were higher than those of the other four subfamilies under infection by Sporisorium scitamineum. Notably, the expression of SsGLYI3.4 showed differences in its expression patterns between the resistant genotype YT93-159 and the susceptible genotype ROC22. Furthermore, we cloned the homologous gene ScGLYI-1 of SsGLYI3.4 from YT93-159, which was constitutively expressed and primarily localized to the chloroplast. Meanwhile, the expression of ScGLYI-1 could be up-regulated by exogenous salicylic acid (SA) and smut pathogen stress, indicating that this gene may play a crucial role in response to pathogen stress in sugarcane. This study would provide a theoretical foundation for further elucidating the function of glyoxalase genes in sugarcane.

The primary bottleneck restricting sugarcane harvesting mechanization in Chinaʼs hilly regions is fragmented terrain combined with narrow-row, high-density planting. This study was aimed to systematically analyze the effects of a two-step mechanical harvesting model on production efficiency, raw material quality, and farmer' income, thereby clarifying its application potential and promotion strategies in these regions. During the 2023/2024 and 2024/2025 harvesting seasons in Gengma, field experiments and cost-benefit analyses were conducted to compare four harvesting models, Combine Harvesting, Traditional Manual, Commissioned Processing, and Raw Cane Sale. Statistical methods, including ANOVA, were employed to analyze the effects of sugarcane growth stages and major cultivars on the impurity rate of raw materials. The Commissioned Processing model increased farmerʼs net income to 365.00 yuan/t over the Traditional Manual model (farmerʼs net income 318.00 yuan/t), an increase of 14.80%, while reducing harvesting costs 42.06%. The income was comparable to the Combine Harvesting model but effectively avoided the severe damage to sugarcane ratoons caused by the latter. Regarding raw material quality, genetic differences among cultivars had no significant effect on the impurity rate, whereas harvest time was the dominant factor. As the harvest period was extended from December to the following April, the net cane rate under Traditional Manual model significantly increased from 75.76% to 84.90%. Correspondingly, the impurity rate of two-step mechanized harvesting decreased from 6.42% to 4.52%, indicating that scheduling operations within the full maturity window after January effectively controls raw material impurities. The study also revealed a misalignment between the commercial impurity deduction standards of sugar mills and field-measured impurity rates. This discrepancy, characterized by significant inter-varietal differences, could hinder the fair promotion of this new technology. The two-step mechanical harvesting model is an optimal choice for Chinaʼs hilly regions, balancing economic benefits with ecological sustainability. Its promotion strategy should prioritize establishing a precise operational timetable based on sugarcane growth stages rather than developing differentiated harvesting systems for existing cultivars. This model would provide a quantifiable and scalable solution for mechanization in hilly sugarcane areas, holding significant practical value and strategic importance for enhancing the competitiveness of national sugar industry and ensuring sugar security.

Phosphorus (P), a crucial nutrient, has a significant impact on the growth, development, and productivity of sweetpotato. Establishing an evaluation system for low-phosphorus tolerance in sweetpotato and screening for low-phosphorus tolerant sweetpotato varieties can provide essential foundational support for the further development, breeding, and utilization of low-phosphorus tolerant sweet potato resources. In this study, 30 sweet potato varieties were selected. Field experiments with phosphorus deficiency were conducted, involving two phosphorus treatment conditions, no phosphorus application (0 kg/hm²) and normal phosphorus supply (110 kg/hm²). At the harvest stage, 14 characteristic traits were measured, including fibrous root fresh weight, lateral root of storage root fresh weight, single storage root fresh weight, storage root fresh weight per plant, storage root number per plant, fibrous root dry weight, lateral root of storage root dry weight, storage root dry weight, leaf fresh weight, stem fresh weight, leaf dry weight, stem dry weight, relative chlorophyll content and root/shoot ratio. The low-phosphorus tolerance coefficient for each index was calculated. Principal component analysis, correlation analysis, and cluster analysis were performed using the comprehensive membership function method to evaluate the low-phosphorus tolerance of each sweet potato cultivar. Principal component analysis showed that the cumulative variance contribution rate of the five principal components reached 80.36%, indicating these indicators fully reflected the low-phosphorus tolerance of sweetpotato varieties. The comprehensive low-phosphorus tolerance evaluation value (D) was calculated via the membership function method, with D values ranging from 0.30 to 0.79. The varieties were classified into four grades, high tolerance, medium tolerance, low tolerance, and non-tolerance. Through systematic cluster analysis, Qiongshu4 was identified as a high-tolerance variety, Silky, Fushu8, and Shanchuanzi were classified as medium-tolerance varieties, Yanshu25, Taishu14, and Xuzishu8 were low-tolerance varieties, and Annayu, Jinshu17, and Xinxiang were low phosphorus-sensitive varieties. The key evaluation indicators for low-phosphorus tolerance in sweet potato at harvest stage were determined to be the yield per plant (storage root fresh weight per plant), fibrous root fresh weight, lateral root of storage root fresh weight, fibrous root dry weight, leaf fresh weight, stem fresh weight, leaf dry weight, and stem dry weight. This study would provide a theoretical basis for breeding and utilizing new low-phosphorus-tolerant sweetpotato varieties.

Calcium-dependent protein kinases (CPKs) are a class of plant-specific key signal transduction factors. In pineapple, an important tropical economic crop, the identification, classification, and functional characterization of the CPKs gene family are still in their infancy, and the molecular mechanisms by which they participate in stress responses remain unclear, which limits their application in the improvement of stress-resistant pineapple varieties. In this study, we systematically investigated the AcoCPKs gene family in pineapple by integrating genomic analysis, chromosomal localization, bioinformatic prediction, and qRT-PCR–based molecular approaches. A total of 18 AcoCPKs family members were identified at the whole-genome level in pineapple. Chromosomal mapping showed that these AcoCPKs genes are unevenly distributed across the nine chromosomes of pineapple. Bioinformatic analysis revealed that all AcoCPKs sproteins share similar conserved motifs and domain architectures. qRT-PCR expression profiling further demonstrated that the 18 AcoCPKs genes are expressed in multiple tissues, including fruits, leaves, fruit peduncles, and flower buds, with distinct tissue-specific expression patterns; moreover, the transcription levels of several AcoCPKs genes were markedly up-regulated under high-temperature, low-temperature, and NaCl salt stress treatments.Taken together, this study systematically elucidates the physicochemical properties, genetic characteristics, and stress-responsive expression patterns of members of the AcoCPKs gene family in pineapple. These findings not only provide an important theoretical basis for further dissecting the molecular mechanisms underlying AcoCPKs-mediated stress responses in pineapple, but also lay a solid foundation for the targeted improvement of stress tolerance and the breeding of high-quality, stress-resistant pineapple cultivars through gene editing, transgenic approaches, and other modern molecular breeding technologies.

The study systematically investigated the long-term regulatory effects of returning sugarcane organic materials to the field on soil physicochemical properties, microbial communities, and sugarcane growth to solve the problems of soil acidification, organic matter attenuation and structural degradation in sugarcane fields on dry slopes in China. Through a three-year barrel planting experiment (including one new planting season and two-year ratoon season), four types of sugarcane organic materials were returned to the field, including filter mud (T₁), sugarcane bagasse ash (T₂), sugarcane leaves (T₃), sugarcane bagasse (T₄), along with control (without organic amendment). Soil nutrients, physical structure, microbial diversity, root morphology, yield and sugar content were measured. The four sugarcane organic materials returned to the field reduced soil bulk density and improved soil mechanical properties and pore structure, but significant difference were observed in the effects of different materials. T₁ and T₂ significantly increased soil pH, total organic carbon (TOC), alkali-hydrolyzable nitrogen (AN) and available phosphorus (AP). T₁ consistently optimized deep soil structure, and T₂ had a significant effect on improving available potassium (AK) and water retention. T₃ and T₄ mainly increased soil TOC content, but T₄ aggravated soil acidification during the new planting season. T₃ and T₄ promoted the formation of highly stable large aggregates, with significant short-term effect. Although T₁ and T₂ promoted the formation of mechanically stable large aggregates, the water stability was poor. T₁ and T₂ had significant and long-lasting effects on improving the diversity and richness of soil bacteria and fungi, T₃ promoted microbial activity in the early stage but inhibited it in the later stages, and T₄ significantly restored microbial diversity in the later stages. T₁ had the most significant effect on increasing yield and sugar content, T₂ had an outstanding effect on promoting root development and had significantly effects on increasing yield and sugar content. T₃ had a certain yield-increasing effect in the later stages. T₄ led to a yield reduction and was not conducive to sugar accumulation. Overall, the effects of returning different sugarcane organic materials to the field varied significantly. Filter mud (T₁) proved to be the optimal material, combining long-term soil improvement, enhanced microbial diversity, and increased yield and sugar content. Sugarcane bagasse ash (T₂) was suitable for short-term water retention and root growth, but the risk of deep soil compaction must be controlled. Sugarcane leaves (T₃) should be accompanied by nitrogen fertilizer. Sugarcane bagasse (T₄) returning to field requires decomposition pretreatment. This study could provides theoretical support for the precise return of sugarcane organic materials to the field and the sustainable management of cultivated land in red soil areas.

Raffinose family oligosaccharides (RFOs) are the most widely distributed oligosaccharides containing galactose (-Gol) in higher plants. Raffinose (Raf) and stachyose (Sta) are the main members of this family, which are used as osmotic agents or active oxygen scavengers in many plants to maintain cell integrity. Glycosyl hydrolase 36 family (GH36) is a kind of α-galactosidase, which can catalyze oligosaccharides containing -Gol to produce RFOs. Hevea brasiliensis is an important plant for synthesizing natural rubber. After tapping and stimulation by exogenous ethylene, glycosyl hydrolases accumulate in latex and play an important role in maintaining latex stability. Eight genes (HbGH36-1-8) of glycosyl hydrolase 36 family (HbGH36) were successfully identified to search for functional hydrolases in the latex of H. brasiliensis. QRT-PCR analysis showed that five genes (HbGH36-1, HbGH36-4, HbGH36-6, HbGH36-7, HbGH36-8) were obviously expressed in latex. Among the five genes, HbGH36-4, HbGH36-6, HbGH36-7 and HbGH36-8 were highly expressed in response to tapping stimulation, and the expression levels of HbGH36-4 and HbGH36-7 changed more obviously. HbGH36-1, HbGH36-4, HbGH36-6 and HbGH36-7 expressed at high levels in response to exogenous ethylene stimulation, and HbGH36-6 expressed at high levels for a relatively long time after ethylene stimulation. Western blot of different components of H. brasiliensis latex confirmed that HbGH36-1 and HbGH36-8 were expressed in C-serum component of latex. The results indicate that H. brasiliensis HbGH36s may be involved in the regulation of latex stability and latex physiological metabolism in response to tapping and ethylene stimulation.

Mango is one of the most widely cultivated and economically significant fruit trees in tropical regions of China, playing a vital role in optimizing agricultural structure and promoting rural revitalization. Scientifically delineating suitable planting zones for mango is essential for precise resource allocation and the high-quality development of the industry. However, most existing studies focus on climatic and topographic factors, with insufficient systematic consideration of soil physicochemical properties. In addition, current suitability evaluations often suffer from strong subjectivity in indicator selection and low integration of evaluation methods. To address these gaps, this study took Sanya city as the research area and developed a comprehensive evaluation model for mango planting suitability. First, the MaxEnt model was employed to identify key environmental factors and extract response curves for constructing membership functions. Second, an improved three-scale Analytic Hierarchy Process (3-scale AHP) and the entropy weight method were applied to determine subjective and objective weights, respectively, which were then integrated using a game theory-based weighting approach. Finally, the study area was classified into three planting suitability zones based on a comprehensive suitability index, and field surveys were conducted for validation. Bulk density, pH, cation exchange capacity (CEC), silt content, total potassium, soil type, slope, elevation, sunshine hours during the fruit maturity and harvest period, and annual maximum temperature were the ten dominant factors, with soil-related variables playing a critical role in the model. The suitable area covered 117 939 hm², accounting for 61% of Sanya's total area, with the most advantageous zones concentrated in southern Yazhou and southern Tianya. Advantageous zones were characterized by "low elevation–slightly acidic–potassium-rich–high permeability–high sunshine" conditions, which are conducive to high and stable mango yields with premium quality. The "factor selection–membership function construction–game theory-based weighting–suitability zoning" evaluation framework proposed in this study would provide both theoretical and methodological support for precision planting of tropical fruit trees and the optimization of regional agricultural spatial layouts.