【作者】 李鑫；

【导师】 徐凡；

【作者基本信息】 沈阳农业大学 ， 作物栽培学与耕作学， 2020， 硕士

【摘要】 自噬是真核生物中一种保守的物质降解途径,对于植物的生长发育和抵御逆境胁迫具有重要作用,本文以水稻自噬相关基因OsATG8c的过表达株系35S-OsATG8c转基因水稻株系为主要研究对象,对该基因的功能进行了初步研究,观察其对水稻植株生长发育的影响以及在氮、碳胁迫和干旱胁迫中发挥的作用。主要结果如下所示:1、通过对Pro_OsATG8c-GUS转基因水稻进行GUS组织化学染色后发现,水稻自噬相关基因OsATG8c在水稻的根、茎、鞘、衰老叶片、新生叶片、孕穗期幼穗以及灌浆期穗部等组织部位都有表达,并对氮胁迫、碳胁迫和干旱胁迫均有响应。2、正常成长条件下,在生长发育方面,过表达OsATG8c降低了水稻的株高,增加了水稻的分蘖数目和生物量,提高了水稻叶片中的叶绿素含量。在产量方面,过表达OsATG8c提高了水稻的单株产量,产量构成因素中,过表达株系水稻的有效穗数显著高于对照SN9816,但结实率和千粒重显著低于SN9816。另外,35S-OsATG8c转基因株系水稻的氮素吸收效率和氮素利用效率均得到了显著提高,但稻米中蛋白质含量上升,直链淀粉含量降低,食味品质下降。3、在低氮条件下,35S-OsATG8c转基因株系对低氮胁迫表现出更高的耐受性,转基因株系拥有更多的分蘖数目和生物量,更高叶绿素含量、氮素吸收效率以及氮素利用效率。MDC染色结果显示,过表达OsATG8c提高了水稻的自噬活性,增加了自噬体数目,水稻在低氮条件下自噬体数目多于正常条件下,且在35S-OsATG8c转基因株系中这一现象更为明显,OsATG8c可能是通过增强水稻自噬能力来提高水稻对氮胁迫的耐受性。4、35S-OsATG8c转基因水稻株系和对照株系SN9816在经过长期黑暗处理后,转基因水稻株系的植株更为健康,可溶性糖和可溶性蛋白含量的变化量更小,过表达OsATG8c提高了水稻对碳饥饿的耐受性。5、在甘露醇模拟干旱胁迫的实验中,过表达OsATG8c基因缓解了干旱胁迫对种子萌发的抑制作用,延缓了干旱条件下水稻幼苗的死亡,提高了水稻对干旱胁迫的耐受性。综上研究结果表明,水稻自噬相关基因OsATG8c在提高水稻产量、氮素吸收效率利用效率等方面具有积极作用,当水稻面临氮胁迫、碳胁迫以及干旱胁迫时,可以提高水稻对这些胁迫的耐受性,对于实现水稻的高产稳产有益。更多还原

【Abstract】 Autophagy is a kind of conservative material degradation pathway in eukaryotes,which plays an important role in the growth and development of plants and resistance to stress.In this study,we confirmed the function of OsATG8c using 35S-OsATG8c in transgenic rice plants.The effect of the gene on the growth and development of rice plants and its role in nitrogen,carbon and drought stress were observed.The main results are as follows: 1.Through GUS histochemical staining of Pro_OsATG8c-GUS transgenic rice,it was found that rice autophagy related gene OsATG8c was expressed in roots,stems,sheaths,senescent leaves,new leaves,young ears at booting stage and ears at filling stage,and it was responsive to nitrogen stress,carbon stress and drought stress.2.Under normal growth conditions,overexpression of OsATG8c decreased plant height,increased tiller number and biomass,and increased chlorophyll content in rice leaves.In terms of yield,overexpression of OsATG8c increased the yield per plant of rice,which increased the number of effective panicles,but reduced the seed setting rate and 1000 grain weight of rice,.In addition,the nitrogen uptake efficiency and nitrogen use efficiency of 35S-OsATG8c transgenic lines were significantly improved,but the protein content in rice increased,the amylose content decreased,and the taste quality decreased.3.Under the condition of low nitrogen,the 35S-OsATG8c transgenic lines showed higher tolerance under low nitrogen stress.The transgenic lines had more tillers and biomass,higher chlorophyll content,nitrogen absorption efficiency and nitrogen use efficiency.MDC staining results showed that overexpression of OsATG8c increased the autophagy activity and the number of autophagy in rice.The number of autophagy in rice was more than that in normal rice under low nitrogen condition,and this phenomenon was more obvious in 35S-OsATG8c transgenic lines.OsATG8c may improve the tolerance of rice to nitrogen stress by enhancing the autophagy ability of rice.4.After a long period of dark treatment,the plants of 35S-OsATG8c transgenic rice lines were healthier,and the changes of soluble sugar and protein content were smaller than SN9816 control line.Overexpression of OsATG8c improved the tolerance of rice to carbon starvation.5.In the experiment of mannitol simulating drought stress,overexpression of OsATG8c gene alleviated the inhibition of drought stress on seed germination,delayed the death of plant under drought.Overexpression of OsATG8c improved the tolerance of rice to drought stress.In conclusion,the results show that the rice autophagy related gene OsATG8c has a positive role in improving rice yield and nitrogen use efficiency.When rice is faced with nitrogen stress,carbon stress and drought stress,it can improve the tolerance of rice to these stresses.It is beneficial to the realization of high and stable yield of rice.更多还原