中国农业科学 ›› 2021, Vol. 54 ›› Issue (7): 1439-1454.doi: 10.3864/j.issn.0578-1752.2021.07.010

• 肥水高效利用 • 上一篇    下一篇

不同施氮水平下灌浆期高温对水稻贮藏蛋白积累及其合成代谢影响

韩展誉1,吴春艳2,许艳秋1,黄福灯2,熊义勤1,管弦悦1,周庐建1,潘刚1,程方民1()   

  1. 1浙江大学农业与生物技术学院,杭州 310058
    2浙江省农业科学院,杭州 310021
  • 收稿日期:2020-08-11 接受日期:2020-09-27 出版日期:2021-04-01 发布日期:2021-04-22
  • 通讯作者: 程方民
  • 作者简介:韩展誉,E-mail:zhanyu-han@qq.com
  • 基金资助:
    国家自然科学基金(31871566);国家重点研发计划(2016YFD0300502);国家重点研发计划(2017YFD0300103)

Effects of High-Temperature at Filling Stage on Grain Storage Protein Accumulation and Its Biosynthesis Metabolism for Rice Plants Under Different Nitrogen Application Levels

HAN ZhanYu1,WU ChunYan2,XU YanQiu1,HUANG FuDeng2,XIONG YiQin1,GUAN XianYue1,ZHOU LuJian1,PAN Gang1,CHENG FangMin1()   

  1. 1College of Agriculture and Biotechnology, Zhejiang University, Hangzhou 310058
    2Zhejiang Academy of Agricultural Sciences, Hangzhou 310021
  • Received:2020-08-11 Accepted:2020-09-27 Online:2021-04-01 Published:2021-04-22
  • Contact: FangMin CHENG

摘要: 【目的】 揭示不同施氮水平下灌浆结实期高温对稻米贮藏蛋白积累及其组分的影响,明确不同温氮处理组合下稻米贮藏蛋白合成积累过程与籽粒氮代谢关键酶及相关基因表达间关系。 【方法】 以2个主栽常规晚粳品种(秀水134和秀水09)为材料,利用盆栽土培试验,在水稻穗分化期设低氮(每盆0.5 g尿素)和高氮(每盆2.0 g尿素)2个氮水平,继而通过在水稻灌浆结实期的人工气候箱控温试验,设置高温(日均温度30℃,日最高温和最低温分别为34℃和26℃)和常温(日均温度23℃,日最高温和最低温分别为26℃和20℃),构成低氮-常温(LN-NT)、低氮-高温(LN-HT)、高氮-常温(HN-NT)、高氮-高温(HN-HT)4个处理组合,并结合水稻籽粒灌浆不同时期取样,探讨氮素穗肥对水稻高温灌浆过程贮藏蛋白积累和主要蛋白组分含量影响及其与籽粒氮代谢关键酶及相关基因表达间关系。 【结果】 氮素穗肥和灌浆期高温均会导致稻米粗蛋白相对含量上升,但在高温处理下单位籽粒中粗蛋白的绝对量却呈降低趋势,以13 kD醇溶蛋白亚基组分在高温处理下的下降幅度最大,从而引起籽粒谷蛋白/醇溶蛋白质比值的上升,其原因主要是由于编码水稻13 kD醇溶蛋白合成基因(Pro13, Pro14Pro17)在高温处理下的下调表达所致。与之相比,增施氮素穗肥(HN-NT和HN-HT)在引起稻米粗蛋白相对含量提升的同时,单位籽粒中的粗蛋白总量、谷蛋白和醇溶蛋白含量均显著增加,但对贮藏蛋白谷/醇比的影响不明显,且谷蛋白组分中的37 kD酸性亚基和22 kD碱性亚基在不同氮处理水平下的相对比例也基本保持稳定;氮素穗肥可增强灌浆籽粒中的谷氨酰胺合酶(GS)、谷草转氨酶(GOT)和谷丙转氨酶(GPT)活性,但HN-HT处理下的籽粒GS、GOT和GPT活性显著低于HN-NT处理,高温胁迫对水稻灌浆中后期籽粒器官中的氮转运代谢具有抑制作用。此外,在不同氮素水平下,灌浆期高温均可引起稻米整精米率的明显下降和垩白度的显著上升,但HN-HT处理的千粒重、结实率、产量水平、整精米率却高于LN-HT处理,且前者的稻米垩白度显著低于后者,氮素穗肥不足加剧了高温胁迫对千粒重、结实率、整精米率和垩白度等产量和品质性状的负面影响。 【结论】 氮素穗肥对水稻高温灌浆过程贮藏蛋白合成积累起重要调节作用,增施氮素穗肥虽然对水稻籽粒灌浆过程中的谷蛋白和醇溶蛋白质合成具有促进作用,并导致稻米贮藏蛋白相对量与绝对量增加,但对于高温灌浆下13kD醇溶蛋白亚基合成及其组分含量下降具有一定程度的缓解效应,有利于维持贮藏蛋白谷/醇比相对稳定。

关键词: 水稻, 贮藏蛋白, 氮肥, 灌浆高温, 稻米品质, 氮代谢

Abstract:

【Objective】The aim of this study was to clarify the interaction effect of high temperature at filling stage and nitrogen fertilizer levels on grain storage protein accumulation and its underlying metabolic mechanism, by investigating the relationship of grain storage protein biosynthesis and its accumulation with the activity of key enzymes involving in nitrogen mobilization and transcriptional expression of various genes that encoded prolamin and pre-glutelin biosynthesis during developing grains.【Method】A two-factor pot experiment, including the combination of two nitrogen fertilizer levels with two temperature regimes, was conducted by using two japonica rice cultivars, namely XS134 and XS 09. The nitrogen fertilizer treatments were conducted at the young panicle differentiation stage of rice plants, with the urea supply of 0.5 g/pot and 2.0 g/pot being considered as low nitrogen (LN) and high nitrogen (HN), respectively. After heading, these rice plants in pots with the same nitrogen fertilizer level (LN or HN) were classified into two groups and then imposed to different temperature regimes in phytotrons, with the daily mean temperature being controlled at 30℃ (34℃/26℃) and 23℃ (26℃/20℃) for high temperature (HT) and normal temperature (NT) as control, respectively. The rice grains under four treatments (LN-NT, LN-HT, HN-NT, and HN-HT) were sampled to examine the impact of high temperature on grain storage protein accumulation and its relation to grain N metabolism under different N levels. 【Result】Both nitrogen fertilizer application at young panicle differentiation stage and HT exposure at filling stage evidently enhanced the relative content of storage protein content in rice grains on dry matter basis. However, HT exposure at filling stage decreased the accumulation amount of grain storage protein on per grain basis, with the dramatically dropping extent for 13-kD prolamin among different protein components. In contrast to NT, HT exposure resulted in a relatively higher ratio of glutelin to prolamin. HT-induced decline in amount of 13-kD prolamin was mainly attributable to the remarkably down-regulating transcripts of prolamin family genes (Pro13, Pro14, and Pro17) under HT exposure. However, the dropping extent of grain prolamin content under HT growth appeared to be smaller for HN relative to LN. Comparatively, HN supply significantly enhanced the amounts of total storage protein, glutelin, and prolamin in rice grains, but it had little impact on the ratio of glutelin to prolamin in rice grains, with the nearly equivalent extent of HN-induced increases in both 37-kD α-glutelin and 22-kD β-glutelin and the relatively stable ratio of 37-kD to 22-kD in glutelin components among different N levels. Furthermore, HN notably enhanced the activities of GS, GOT, GPT in rice grains at the middle-late stages of grain filling, but HN-NT had significantly lower activities of GS, GOT, GPT than HN-NT, implying that HT had an inhibitory impact on HN-induced enhancements in N transferring metabolism in rice grains. Under different N levels, HT resulted in the lowering HMR (heading milled rate) and increasing chalky rate. In contrast, HN-HT had relatively heavier grain weight, higher seed-setting rate, higher HMR and lower chalky grain rate than LN-HT, indicating that N deficiency exacerbated the negative impact of HT on some rice yield and grain quality traits, including grain weight, seed-setting rate, HMR, chalky grain rate, etc.【Conclusion】Nitrogen fertilizer application at young panicle differentiation stage play a regulatory role in the effect of HT exposure at filling stage on storage protein biosynthesis and its accumulation in rice grains. Heavy N application evidently accelerated the glutelin and prolamin biosynthesis in filling grains and significantly enhance the total accumulation amount of grain storage protein both on dry matter basis and on per grain basis, but it contribute to the alleviation for HT-induced decline in 13-kD prolamin biosynthesis and its accumulation amount in rice grains. This occurrence was beneficial to the maintenance of the relatively stable ratio of glutelin to prolamin in HT-ripening grains .

Key words: rice (Oryza sativa L.), storage protein, nitrogen fertilizer, high temperature, grain quality, nitrogen metabolism