水稻-冬季秸秆覆盖种植马铃薯模式对水稻齐穗期根际土壤代谢组表达特征的影响

Effects of Rice-potato with Straw Mulch in Winter on Soil Metabolite Expression in Rice Rhizosphere at Full-heading Stage

水稻–冬季秸秆覆盖种植马铃薯是南方稻区一种经济高产的水–旱轮作模式,其对水稻根际土壤代谢物的影响可能是调控水稻高产的关键,但目前相关研究尚未见报道。本研究基于周年水–旱轮作模式长期定位试验,以水稻–冬季空闲(CK)模式为对照和水稻–马铃薯(稻草覆盖种植并还田,RP)轮作模式为研究对象,采集水稻齐穗期根际土壤样品,利用液相色谱–质谱法(LC-MS)测定根际土壤代谢物种类与丰度,研究RP轮作模式水稻齐穗根际土壤代谢物组分和功能及其与产量形成的关系。结果表明:①采用OPLS-DA模型筛选差异代谢物(HMDB数据库)发现,与CK模式相比,RP轮作模式具有201个有显著性差异(P<0.05)的根际土壤代谢物,分别归属于脂质和类脂分子、有机酸及衍生物、有机氧化合物、苯丙烷和聚酮等11个父类;其中苯丙烷和聚酮、丙烯醇脂质、苯及其衍生物、甾体内酯、氨基酸/肽、碳水化合物和脂肪酰糖苷等代谢物丰度发生显著变化,可作为表征RP轮作模式下水稻根际土壤差异性代谢物;②有机氧化合物、有机酸及衍生物和苯丙烷和聚酮等代谢物丰度与土壤有机质、全钾、碱解氮和速效钾含量差异呈显著正相关(r=0.816~0.938),其可通过为水稻直接提供养分、协助提高土壤养分供给或间接调节水稻生长等提高稻田综合生产力;③核苷/核苷酸、脂质和类脂分子等差异代谢物与水稻产量差异呈显著正相关(r=0.957~0.999),其可能是通过参与一系列代谢途径提高水稻抗逆能力,最终对水稻产量产生一定影响。

Rice-potato with straw mulch in winter is an economical and high-yield paddy-upland rotation system in southern China,and its effects on soil metabolites in rhizosphere may be the key to achieve the rice yield potential but it is still unclear.Based on a long-term experiment of paddy-upland rotation(since 2003 Fuyang of Zhejiang),the rice-fallow(CK)was set as control and composition and possible function of soil rhizosphere metabolites of rice-potato(straw mulch and return,RP)were evaluated.The rhizosphere soil samples were collected at full heading stage using“root bags”and evaluated by Liquid Chromatography-Mass Spectrometry(LC-MS).The results show that:1)By using the OPLS-DA model,201 different expressed rhizosphere soil metabolites(VIP>1 and P<0.05)are screened out under the RP rotation,as compared to that under CK,and these metabolites are attributed to 11 super-class,such as lipids and lipid-like molecules,organic acids and derivatives,organic oxygen compounds,etc.(based on HMDB database).In addition,the abundances of phenylpropanoids and polyketides,prenol lipids,benzene and substituted derivatives,steroid lactones,amino acids/peptides,carbohydrates and fatty acyl glycosides are changed significantly in response to the change of rotation from CK to RP,which indicate that these metabolites could be used as characteristics traits of rhizosphere soil metabolites of rice to distinguish the RP rotation from CK.2)Organic oxygen compounds,organic acids and derivatives,phenylpropanoids and polyketides have significant positive correlation with the differences of soil organic matter,total potassium,available nitrogen and available potassium(r=0.816-0.938),which not only provide the nutrient matter directly or indirectly,but also assist in promoting the rice growth.3)Phenylpropanoids and polyketides,nucleosides/nucleotides and analogues,lipids and lipid-like molecules,which have significant positive correlation with rice grain yield(r=0.957-0.999),might improve the stress resistance of rice by participating in a series of metabolic pathways.