Department of Soil and Environmental Sciences, National Chung Hsing University, Taichung City 40227, Taiwan.
Innovation and Development Center of Sustainable Agriculture (IDCSA), National Chung Hsing University, Taichung City 40227, Taiwan.
Lett Appl Microbiol. 2023 Jan 23;76(1). doi: 10.1093/lambio/ovac035.
The aim of this study was to develop an efficient bioinoculant for amelioration of adverse effects from chilling stress (10°C), which are frequently occurred during rice seedling stage. Seed germination bioassay under chilling condition with rice (Oryza sativa L.) cv. Tainan 11 was performed to screen for plant growth-promoting (PGP) bacteria among 41 chilling-tolerant rice endophytes. And several agronomic traits were used to evaluate the effects of bacterial inoculation on rice seedling, which were experienced for 7-d chilling stress in walk-in growth chamber. The field trials were further used to verify the performance of potential PGP endophytes on rice growth. A total of three endophytes with multiple PGP traits were obtained. It was demonstrated that Pseudomonas sp. CC-LS37 inoculation led to 18% increase of maximal efficiency of Photosystem II (PSII) after 7-d chilling stress and 7% increase of chlorophyll a content, and 64% decline of malondialdehyde content in shoot after 10-d recovery at normal temperature in walk-in growth chamber. In field trial, biopriming of seeds with strain CC-LS37 caused rice plants to increase shoot chlorophyll soil plant analysis development values (by 2.9% and 2.5%, respectively) and tiller number (both by 61%) under natural climate and chilling stress during the end of tillering stage, afterward 30% more grain yield was achieved. In conclusion, strain CC-LS37 exerted its function in increase of tiller number of chilling stress-treated rice seedlings via improvement of photosynthetic characteristics, which in turn increases the rice grain yield. This study also proposed multiple indices used in the screening of potential endophytes for conferring chilling tolerance of rice plants.
本研究旨在开发一种有效的生物接种剂，以改善水稻幼苗期经常发生的冷胁迫（10°C）的不良影响。采用水稻（Oryza sativa L.）品种 Tainan 11 在冷胁迫条件下进行种子萌发生物测定，从 41 种耐冷水稻内生菌中筛选具有植物促生（PGP）特性的细菌。并采用几种农艺性状评价细菌接种对水稻幼苗的影响，这些幼苗在步行式生长室内经历了 7 天的冷胁迫。进一步进行田间试验以验证潜在 PGP 内生菌对水稻生长的性能。共获得具有多种 PGP 特性的 3 种内生菌。结果表明，在冷胁迫 7 天后，接种 Pseudomonas sp. CC-LS37 可使 PSII 的最大效率提高 18%，叶绿素 a 含量增加 7%，在步行式生长室内恢复正常温度 10 天后，茎中的丙二醛含量降低 64%。在田间试验中，用菌株 CC-LS37 对种子进行生物引发可使水稻植株在自然气候和分蘖末期冷胁迫下增加地上部叶绿素土壤植物分析发展值（分别增加 2.9%和 2.5%）和分蘖数（均增加 61%），随后可获得 30%的更多籽粒产量。总之，菌株 CC-LS37 通过改善光合特性来发挥其功能，从而增加冷胁迫处理水稻幼苗的分蘖数，进而提高水稻的籽粒产量。本研究还提出了用于赋予水稻耐冷性的潜在内生菌筛选的多个指标。
