Implication of the hydrogen recycling capacity of rhizobia inoculants on the drought stress resistance of legume crops

根瘤菌接种剂的氢循环能力对豆科作物抗旱性的影响

• 批准号: 580215-2022
• 负责人: Constant, PhilippeP
• 金额: $ 1.82万
• 依托单位: Institut national de la recherche scientifique
• 依托单位国家: 加拿大
• 项目类别: Alliance Grants
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=743842
• 关键词: Implication; hydrogen; recycling; capacity; rhizobia

Besides the input of nitrogen in soil supported by legume crops, leakage of molecular hydrogen (H2) from nitrogen-fixing nodules is envisioned as a significant contributor to the crop rotation effect. Being an obligatory by-product of the nitrogen fixation reaction, large amounts of H2 are produced in agroecosystems, representing 240 000 liters per hectare per growing season according to previous estimates. However, there are nitrogen-fixing rhizobacteria endowed with the ability to capture the H2 produced, but these latter are rarely found in natural symbioses, whereas they are dominant in commercial inoculants. Two schools of thought attempt to explain this paradox. The first stipulates that rhizobium-legume symbioses recycling H2 (Hup+) are more effective in improving the energy balance of the symbiosis, justifying the interest in integrating them into commercial inoculants. The second sees H2 leakage from rhizobium-legume symbioses that do not recycle H2 (Hup-) as a currency for the enrichment of H2-oxidizing bacteria (BOH), using the gas as a source of energy in soil. BOH are ubiquitous in soil and are represented by several species that promote plant growth and stress tolerance. Could a transition to Hup- nitrogen-fixing rhizobium inoculants help improve crop resilience to climate change? This issue will be addressed through a workshop guiding the preparation of a review article to be held in Spain and through research activities that will be carried out to examine the impact of H2 leakage on plant tolerance to drought. Theoretical and experimental data will provide the first mechanistic information on the impact of H2 emitted by nitrogen-fixing nodules on "rhizobium-plant-microbe-soil" interactions. The results will be shared with Canadian pulse growers facing an increase in the frequency of drought events, consolidating new partnerships and guiding their selection of inoculants.

除了豆类作物支持的土壤中的氮输入外，从固氮结核中泄漏的分子氢（H2）被认为是作物轮作效应的重要贡献者。作为固氮反应的必然副产品，农业生态系统中会产生大量氢气，根据之前的估计，每个生长季节每公顷产生 240 000 升氢气。然而，固氮根际细菌具有捕获产生的氢气的能力，但后者很少在自然共生中发现，而它们在商业接种剂中占主导地位。两种思想流派试图解释这一悖论。第一条规定，根瘤菌-豆科植物共生体回收 H2 (Hup+) 在改善共生体的能量平衡方面更有效，证明了将它们整合到商业接种剂中的兴趣。第二个观点是根瘤菌-豆科植物共生体中的氢气泄漏，这些共生体不会将氢气（Hup-）回收作为富集氢气氧化细菌（BOH）的货币，而是将气体用作土壤中的能源。 BOH 在土壤中普遍存在，并以多种促进植物生长和抗逆性的物种为代表。向 Hup 固氮根瘤菌接种剂的过渡是否有助于提高作物对气候变化的适应能力？该问题将通过在西班牙举行的指导撰写综述文章的研讨会以及研究氢气泄漏对植物耐旱性影响的研究活动来解决。理论和实验数据将提供关于固氮结核释放的氢气对“根瘤菌-植物-微生物-土壤”相互作用影响的第一个机制信息。研究结果将与面临干旱事件频率增加的加拿大豆类种植者分享，巩固新的合作伙伴关系并指导他们选择接种剂。