辣椒杂交育种对养分和微生物群落结构的影响

Impacts of pepper hybrid breeding on nutrient dynamics and microbial community structure

摘要:

目的 探究辣椒杂交子代高产的机制，从植株养分、根际土壤、微生物群落、功能基因等维度解析亲子代差异。方法 测定亲子代的产量，以及根、果、根际土的氮、磷、钾含量和根际土壤理化性质；采用高通量测序分析根内、根际微生物群落，利用宏基因组测序明确根际养分代谢相关基因的丰度差异。结果 子代产量显著提升，其中Z3的增幅最高。果实普遍钾含量较高，Z3根部氮、磷超亲积累；根内微生物群落亲子代更替明显，子代富集戴氏菌属(Dyella)、伯克霍尔德氏菌-卡巴拉氏菌-拟伯克霍尔德氏菌属(Burkholderia-Caballeronia-Paraburkholderia)、木霉菌属(Trichoderma)等功能菌属，且这些菌属与养分吸收显著关联；根际土壤有效磷超亲、pH下降，Z3具备全氮高储备和有机质提升的优势；子代磷、钾代谢基因丰度超亲，Z3表现最为显著。结论 子代产量超亲是根际环境、微生物和植株协同作用的结果。杂交后子代通过富集Dyella等功能菌构建高效微生态系统，以磷、钾代谢基因丰度提升强化养分代谢效率，最终形成了根部高效吸收和果实高效转运的优势。研究结果为解析作物亲子代养分利用差异的微生物驱动机制提供了新的理论框架，也丰富了植物-微生物-土壤互作的理论。

Abstract:

Objective To unravel the mechanism underlying the high-yield performance of hybrid pepper (Capsicum annuum L.) progenies and dissect parent-progeny differences across four interconnected dimensions: plant nutrient accumulation, rhizosphere soil physicochemical properties, microbial community composition, and nutrient metabolism-related functional genes.Methods For both parental lines and their hybrid progenies, the yields and the content of nitrogen (N), phosphorus (P), and potassium (K) in roots, fruits, and rhizosphere soil were determined, alongside rhizosphere soil physicochemical properties. High-throughput sequencing was adopted to analyze the structures of root endophytic and rhizosphere microbial communities, while metagenomic sequencing was used to quantify the abundance differences of genes associated with rhizosphere nutrient metabolism.Results Hybrid progenies exhibited a significant yield increase, with the highest yield increase observed in the Z3 line. All hybrids showed elevated K content in fruits, and Z3 specifically achieved transgressive accumulation of N and P in roots. A distinct turnover of the root endophytic microbial community was detected between parents and progenies. In the hybrids, functional genera including Dyella, Burkholderia-Caballeronia-Paraburkholderia, and Trichoderma were enriched, which were significantly correlated with plant nutrient uptake. In terms of rhizosphere soil properties, all hybrids had higher available phosphorus content and lower rhizosphere pH than parental lines. Notably, Z3 possessed unique advantages of high total nitrogen reserve and increased organic matter content in the rhizosphere. Additionally, the abundance of genes related to P and K metabolism was higher in hybrids than in parents, which was particularly prominent in Z3.Conclusion The transgressive yields of pepper hybrids is driven by the synergy among the rhizosphere environment, microbial communities, and the host plant. Specifically, hybrid progenies constructed an efficient microecosystem by enriching functional microbes (e.g., Dyella) and enhanced nutrient metabolism efficiency through increased abundance of P and K metabolism-related genes. These improvements ultimately led to the formation of nutrient utilization advantages, characterized by efficient nutrient absorption in roots and effective nutrient translocation to fruits. This study provides a novel theoretical framework for deciphering the microbial-driven mechanisms underlying parent-progeny differences in nutrient use efficiency of crops and further enriches the theory of plant-microbe-soil interactions.