利用根圈益生菌提升台梗九號水稻秧苗對鹽逆境的耐受性

Application of Plant Growth-Promoting Rhizobacteria to Improve Salt Stress Tolerance in Rice (Oryza sativa L. cv. TK9) Seedlings

邱莉文(Li-Wen Chiu) ； 黃紹綺(Shao-Chi Huang) ； 李淑君(Sook-Kuan Lee) ； 郭志鴻(Chih-Horng Kuo) ； 盧虎生(Huu-Sheng Lur) ； 劉啟德(Chi-Te Liu)

《台灣農學會報》 18卷3&4期 (2017/12) Pp. 257-274

https://doi.org/10.6730/JAAT.201712_18(3-4).0004

摘要

全球性氣候變遷對農業的衝擊甚鉅，嚴重影響了農產品的品質與數量。近年來許多研究發現當植物遭遇到包括乾旱、鹽害、極端氣溫等逆境時，接種「促進植物生長之根圈細菌」（Plant Growth Promoting Rhizobacteria, PGPR）可有效抵抗或緩和逆境因子對植物生長生理的衝擊。本研究的目的為評估水稻根圈細菌Oryzomicrobium terrae TPP412以及光合細菌Rhodopseudomonas palustris PS3這兩株PGPR菌株對於台梗九號水稻秧苗的鹽逆境緩解效果。實驗結果發現無論是接種單一菌株或是混合菌株皆可緩解水稻秧苗之鹽逆境（100 mM NaCl），使得鹽害指數下降。但是只有在單獨添加TPP412發酵液的處理組其各項農藝性狀（鮮乾重與含水量等）皆高於控制組，且對於根系生長的促進作用大於對地上部生長的影響。我們在TPP412的全基因體序列中發現該菌株具有生合成吲哚－3－乙酸（IAA）所需的相關基因（位在兩條不同的色氨酸代謝路徑上），加上先前證明TPP412能夠在色氨酸存在下產生植物激素IAA，我們因而推測TPP412應可利用水稻秧苗的根泌出液合成IAA而促進根系發育。進一步比對TPP412的全基因體序列發現該菌株具有合成超氧化物歧化酶（superoxide dismutase, SOD）以及過氧化氫酵素（Catalase, CAT）相關的sodB與katG等同源基因以及與脯氨酸（proline）合成有關的proA、proB與proC基因，因此我們推測TPP412可以藉由調節滲透壓和消除氧化逆境幫助水稻在高鹽環境下生長。

關鍵字

促進植物生長之根圈細菌 ； 鹽逆境 ； 吲哚乙酸 ； 氧化逆境 ； 氣候變遷

並列摘要

Global climate change has already negatively affected agriculture in both quality and quantity of crop production. In recent years, a lot of studies have indicated that some particular plant growth-promoting rhizobacteria (abbreviated as PGPR) can alleviate environmental adversity, such as drought, salinity stress, extreme temperatures and other stresses for plants. Two PGPR strains were utilized in this study, including Oryzomicrobium terrae strain TPP412 and a phototrophic bacterium, Rhodopseudomonas palustris strain PS3. The aim of this study was to evaluate the effects of these PGPR for alleviation of damage from salt stress (100 mM NaCl) on rice seedling growth. The experimental results showed that both the single-strain and mixed-strains inoculant could alleviate the salt stress of rice seedlings, and the salt injury score was decreased. However, only treating with the fermentation broth of TPP412 had better performance in the agronomic traits (including fresh/dry weights and water content, etc)than the control group (CK). Moreover, the promoting effects of TPP412 inoculant on root growth was much stronger than that on shoot growth. We identified some genes involved in two tryptophan dependent pathways for indole-3-acetic acid (IAA) biosynthesis in the whole genome of TPP412. Furthermore, this bacterium was proved to be able to produce IAA in the presence of tryptophan. Accordingly, we hypothesized that TPP412 utilizes the root exudate of rice seedlings to synthesize IAA for promoting root architecture and development. We also identified several osmoprotectant and antioxidant related genes, such as proA, proB, proC, sodB , and katG in the TPP412 genome. Therefore, we speculate that TPP412 can help rice seedlings to grow under high salinity by regulating osmotic pressure and eliminating oxidative stress.

並列關鍵字

Plant growth-promoting rhizobacteria (abbreviated as PGPR) ； salt stress ； indole-3-acetic acid (IAA) ； oxidative stress ； climate change

參考文獻

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