UNASSIGNED: Soil samples were collected from 0-20, 20-40, and 40-60 cm (topsoil, middle layer, and subsoil, respectively) under coniferous Pinus massoniana (PM), broadleaved Erythrophleum fordii (EF), and their mixed (PM/EF) plantation in subtropical China. Used metagenomic sequencing to examine the alterations of relative abundances and molecular ecological network structure of soil P-cycling functional genes after the conversion of plantations.
UNASSIGNED: The composition of P-cycling genes in the topsoil of PM stand was significantly different from that of PM/EF and EF stands (p < 0.05), and total phosphorus (TP) was the main factor causing this difference. After transforming PM plantation into EF plantation, the relative abundances of P solubilization and mineralization genes significantly increased in the topsoil and middle layer with the decrease of soil TP content. The abundances of P-starvation response regulation genes also significantly increased in the subsoil (p < 0.05), which may have been influenced by soil organic carbon (SOC). The dominant genes in all soil layers under three plantations were phoR, glpP, gcd, ppk, and ppx. Transforming PM into EF plantation apparently increased gcd abundance in the topsoil (p < 0.05), with TP and NO3 --N being the main influencing factors. After transforming PM into PM/EF plantations, the molecular ecological network structure of P-cycling genes was more complex; moreover, the key genes in the network were modified with the transformation of PM plantation.
UNASSIGNED: Transforming PM into EF plantation mainly improved the phosphate solubilizing potential of microorganisms at topsoil, while transforming PM into PM/EF plantation may have enhanced structural stability of microbial P-cycling genes react to environmental changes.
■从0-20、20-40和40-60cm收集土壤样品(表土,中间层,和底土,分别)在针叶松马尾松(PM)下,阔叶红回肠(EF),及其在亚热带中国的混合(PM/EF)人工林。利用宏基因组测序技术研究了人工林转换后土壤P循环功能基因的相对丰度和分子生态网络结构的变化。
■PM林分表层土壤中P循环基因的组成与PM/EF和EF林分存在显着差异(p<0.05),总磷(TP)是造成这种差异的主要因素。将PM人工林改造为EF人工林后,随着土壤TP含量的降低,表层和中层的磷溶解和矿化基因的相对丰度显着增加。P-饥饿反应调控基因的丰度在底土中也显著增加(p<0.05),这可能受到土壤有机碳(SOC)的影响。三个人工林下所有土壤层的显性基因均为phoR,glpP,GCD,ppk,和ppx。将PM转化为EF人工林明显增加了表层土壤中的gcd丰度(p<0.05),TP和NO3--N是主要影响因素。在将PM转化为PM/EF种植园后,P循环基因的分子生态网络结构较为复杂;随着PM人工林的转化,网络中的关键基因被修饰。
■将PM转化为EF种植园主要提高了微生物在表土上的磷酸盐溶解潜力,而将PM转化为PM/EF种植园可能增强了微生物P循环基因对环境变化的结构稳定性。