轉錄體分析探討叢枝菌根菌提高水稻鹽耐受性之機制

Transcriptome analysis provides insights into the underlying mechanism of salt tolerance in rice (Oryza sativa japonica cv. Nipponbare) colonized by arbuscular mycorrhizal fungi

陳昀鑫(Yun-Hsin Chen)

指導教授 ： 楊淑怡

國立臺灣大學/生命科學院/植物科學研究所/碩士(2021年)

https://doi.org/10.6342/NTU202100250

摘要

土壤鹽化是導致世界各地農耕地退化的重要因素之一，其影響了水稻的產量。叢枝菌根菌 (arbuscular mycorrhiza fungi, AMF) 與大多數維管束植物形成一個真菌與植物之間的共生關係，在植物的營養吸收和逆境耐受性方面扮演了一個相當重要的角色。雖然過去研究中已發表了水稻在接種叢枝菌根菌後，發揮了在鹽逆境下的正向效益，有關叢枝菌根菌如何提高水稻的鹽耐受性之分子調控機制仍然不夠明瞭。在鹽逆境下，相較於未接種的水稻植株，水稻接種了叢枝菌根菌後顯示出較高的生物質量、提高了無機磷的吸收、減少了植株中鈉離子的含量，並可維持較高的鉀/鈉比值以及較好的小穗(spikelet)發育。為了進一步了解造成這些影響的原因，我們透過核糖核酸測序(RNA-sequencing)的方法以尋找哪些可能是叢枝菌根菌影響水稻對鹽逆境反應相關的差異表達基因。在本研究中，從水稻地上部與根部中分別找到了1081與723個只在鹽逆境時被菌根菌調控表現的候選基因。將候選基因透過Gene ontology和MapMan進行功能性分析後，結果顯示叢枝菌根菌在地上部調控的候選基因參與了蛋白酪氨酸激酶活性(protein tyrosine kinase activity)、過氧化酶活性(peroxidase activity)、細胞壁修飾(cell wall modification)、轉運蛋白(transport)以及光合作用(photosynthesis); 而在根部中受叢枝菌根菌調控的候選基因中，則參與了蛋白酪氨酸激酶活性(protein tyrosine kinase activity)、轉運蛋白(transporter)以及萜類化合物生合成(terpenoid synthesis)。此外，過氧化酶活性測定與DAB染色(3,3'-diaminobenzendine)的結果顯示，叢枝菌根菌提高了水稻地上部在鹽逆境下清除活性氧物種(reactive oxygen species, ROS)的能力。本研究揭示了叢枝菌根菌調控水稻鹽耐受性之可能機制。

關鍵字

水稻 ； 鹽逆境 ； 轉錄體分析 ； 叢枝菌根菌 ； 蛋白酪氨酸激酶活性 ； 活性氧物種

並列摘要

Soil salinity was one of the major causes of agricultural soil degradation worldwide that affected rice production. Arbuscular mycorrhiza fungi (AMF) form a symbiotic relationship between fungi and most vascular plants, which plays a critical role in nutrient absorption and stress tolerance. Although previous studies have addressed the possible benefits of AMF inoculation for rice plants under saline conditions, the underlying molecular mechanisms are still unclear. Compared with mock (non-mycorrhizal) plants, mycorrhizal plants showed higher biomass production, higher phosphate uptake, lower Na+ uptake, higher K+/Na+ ratio, and better spikelet development under 150 mM NaCl salt stress. To explain these phenotypes, we performed RNA sequencing to find differentially expressed genes (DEGs) responding to AM symbiosis especially under salt stress. A total of 1081 and 723 AM-regulated DEGs in rice shoots and roots were identified only under salt stress, respectively, which were considered as our candidate genes. In rice shoots, Gene Ontology (GO) enrichment analysis and MapMan analysis indicated that candidate genes were related to the functional annotations of “protein tyrosine kinase activity”, “peroxidase activity”, “cell wall modification”, “transport”, and “photosynthesis”. In rice roots, candidate genes were related to the functional annotations of “protein tyrosine kinase activity”, “transporter”, and “terpenoid synthesis”. In addition, our results showed that AMF improved ROS scavenging capacity in rice shoots under salt stress. Our study revealed a possible mechanism involved in AM-induced salt tolerance in rice.

並列關鍵字

Oryza sativa ； salt stress ； transcriptome analysis ； arbuscular mycorrhizal fungi ； protein tyrosine kinase activity ； ROS

參考文獻

Acosta-Motos, J. R., Ortuño, M. F., Bernal-Vicente, A., Diaz-Vivancos, P., Sanchez-Blanco, M. J., Hernandez, J. A. (2017). Plant responses to salt stress: adaptive mechanisms. Agronomy, 7(1), 18.

Adesemoye, A., Torbert, H., Kloepper, J. (2008). Enhanced plant nutrient use efficiency with PGPR and AMF in an integrated nutrient management system. Canadian Journal of Microbiology, 54(10), 876-886.

Afzal, Z., Howton, T., Sun, Y., Mukhtar, M. S. (2016). The roles of aquaporins in plant stress responses. Journal of Developmental Biology, 4(1), 9.

Ahmad, P., Jaleel, C. A., Salem, M. A., Nabi, G., Sharma, S. (2010). Roles of enzymatic and nonenzymatic antioxidants in plants during abiotic stress. Critical Reviews in Biotechnology, 30(3), 161-175.

Allison, S. D., Schultz, J. C. (2004). Differential activity of peroxidase isozymes in response to wounding, gypsy moth, and plant hormones in northern red oak (Quercus rubra L.). Journal of Chemical Ecology, 30(7), 1363-1379.