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??轉(zhuǎn)自“中關(guān)村NMT聯(lián)盟”

期刊：BMC Plant Biology

主題：油菜素內(nèi)酯促黃瓜根系銨硝吸收機(jī)制

標(biāo)題：24-Epibrassinolide promotes NO3- andNH4+ ion flux rate and NRT1 gene expression in cucumber under suboptimal root zone temperature

影響因子：3.930

檢測(cè)指標(biāo)：NO3-、NH4+流速

檢測(cè)部位：根毛區(qū)

作者：中國(guó)農(nóng)業(yè)科學(xué)院蔬菜與花卉研究所Ali Anwar、李衍素、于賢昌

英文摘要

Suboptimal root zone temperature (RZT) causes a remarkable reduction in growth of horticultural crops during winter c*tion under greenhouse production. However, limited information is available on the effects of suboptimal RZT on nitrogen (N) metabolism in cucumber seedlings. The aim of this study is to investigate the effects of 24-Epibrassinolide (EBR) on nitrate and ammonium flux rate, N metabolism, and transcript levels of NRT1 family genes under suboptimal RZT in cucumber seedlings.

Suboptimal RZT (LT) negatively affected on cucumber growth and proportionately decreased EBR contents, bleeding rate, root activity, enzyme activities of nitrate reductase (NR), nitrite reductase (NiR), glutamine synthetase (GS), and glutamate synthase (GOGAT), nitrate (NO3−) influx rate, ammonium (NH4+) efflux rate, and transcript levels of nitrate transporter (NRT1) encoding genes. However, exogenous EBR reduced the harmful effects of suboptimal RZT and increased endogenous EBR contents, bleeding rate, root activity, enzyme activities of NR, NiR, GS, and GOGAT, NH4+ and NO3− flux rates and contents, and N accumulation. EBR-treated seedlings also upregulated the transcript levels of nitrate transporters CsNRT1.1, CsNRT1.2A, CsNRT1.2B, CsNRT1.2C, CsNRT1.3, CsNRT1.4A, CsNRT1.5B, CsNRT1.5C, CsNRT1.9, and CsNRT1.10, and downregulated CsNRT1. and CsNRT1.8. LT treatment upregulated the expression level of CsNRT1., while exogenous BZR application downregulated the expression level of NRT1 genes.

These results indicate that exogenous application of EBR alleviated the harmful effects of suboptimal RZT through changes in N metabolism, NH4+ and NO3− flux rates, and NRT1 gene expression, leading to improved cucumber seedlings growth. Our study provides the first evidence of the role of EBR in the response to suboptimal RZT in cucumber, and can be used to improve vegetable production.

中文摘要（谷歌機(jī)翻）

次優(yōu)根區(qū)溫度（RZT）導(dǎo)致在溫室生產(chǎn)期間冬季栽培期間園藝作物的生長(zhǎng)顯著減少。然而，關(guān)于次優(yōu)RZT對(duì)黃瓜幼苗中氮（N）代謝的影響的信息有限。本研究的目的是研究24-表油菜素內(nèi)酯（EBR）對(duì)黃瓜幼苗次優(yōu)RZT下NRT1家族基因的**鹽和銨通量，N代謝和轉(zhuǎn)錄水平的影響。

次優(yōu)RZT（LT）對(duì)黃瓜生長(zhǎng)有負(fù)面影響，并且比例降低EBR含量，出血率，根系活力，**還原酶（NR），亞**還原酶（NiR），谷氨酰胺合成酶（GS）和谷氨酸合成酶（GOGAT）的酶活性，**鹽（NO3-）流入速率，銨（NH4 +）流出速率和**鹽轉(zhuǎn)運(yùn)蛋白（NRT1）編碼基因的轉(zhuǎn)錄水平。然而，外源EBR降低了次優(yōu)RZT的有害作用，增加了內(nèi)源EBR含量，出血率，根系活力，NR，NiR，GS和GOGAT的酶活性，NH4 +和NO3-通量率和含量以及N積累。 EBR處理的幼苗也上調(diào)了**鹽轉(zhuǎn)運(yùn)蛋白CsNRT1.1，CsNRT1.2A，CsNRT1.2B，CsNRT1.2C，CsNRT1.3，CsNRT1.4A，CsNRT1.5B，CsNRT1.5C，CsNRT1.9和CsNRT1的轉(zhuǎn)錄水平。 .10，并下調(diào)CsNRT1.和CsNRT1.8。 LT處理上調(diào)CsNRT1.的表達(dá)水平，而外源BZR應(yīng)用下調(diào)NRT1基因的表達(dá)水平。

這些結(jié)果表明，外源施用EBR通過(guò)改變N代謝，NH4 +和NO3-通量率以及NRT1基因表達(dá)減輕了次優(yōu)RZT的有害作用，從而改善了黃瓜幼苗的生長(zhǎng)。我們的研究證明了EBR在黃瓜中對(duì)次優(yōu)RZT的反應(yīng)中的作用，并可用于改善蔬菜生產(chǎn)。

Fig. 4 Effects of suboptimal RZT and EBR on NO3- (A; scatter NO3- flux rate, B; average NO3- flux rate) flux rate in roots of cucumber seedlings under suboptimal RZT treatment. Flux rate was recorded for 10 min in roots seven days after treatment. Each point is the mean of nine individual seedlings and bars indicate standard deviations. Treatments with the same letters are not significantly different by the least significant difference (LSD) test at P = 0.05