Nitric oxide mediates strigolactone signaling in auxin and ethylene-sensitive lateral root formation in sunflower seedlings
Nitric oxide mediates strigolactone signaling in auxin and ethylene-sensitive lateral root formation in sunflower seedlings
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DOI：
10.1080/15592324.2015.1054087
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发表时间：
2015-08-03
影响因子：
2.9
通讯作者：
Bhatla, Satish C.
中科院分区：
文献类型：
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作者：
Bharti, Niharika;Bhatla, Satish C.
独脚金内酯 (SL) 在塑造根结构中发挥着重要作用，在 SL 介导的初生根伸长、侧根形成和不定根 (AR) 起始反应中观察到生长素-SL 串扰。 GR24（一种合成的独脚金内酯）抑制 LR 和 AR 的形成，而 SL 生物合成抑制剂（氟啶酮）的作用恰恰相反（根增殖）。萘基邻苯二甲酸 (NPA) 会导致 LR 增殖，但完全抑制 AR 发育。响应 GR24、氟啶酮或 NPA 处理，PIN1 在根分化区前维管细胞中的扩散分布进一步表明局部生长素积累参与 LR 发育反应。 GR24 处理对 LR 形成的抑制与 ACC 合酶活性的抑制同时发生。氟啶酮和 NPA 处理的大量 LR 发育与顶端区域和 LR 分化区 [Ca2+](cyt) 的增强相关，表明 [Ca2+] 在 LR 发育中响应生长素、乙烯和 SL 的协调作用而发挥关键作用。在 cPTIO（NO 清除剂）存在下，组织匀浆中类胡萝卜素裂解双加氧酶 (CCD) 活性（负责 SL 生物合成的酶）显着增强，表明内源性 NO 作为 CCD 活性负调节剂的作用。 NO在主根和侧根中空间分布的差异进一步凸显了NO在SL调节的向日葵幼苗根形态发生中的参与。目前的工作提供了关于在 SL 调节的 LR 发育过程中通过内源性一氧化氮调节 CCD 活性对 SL 生物合成进行负调节的新报告。
Strigolactones (SLs) play significant role in shaping root architecture whereby auxin-SL crosstalk has been observed in SL-mediated responses of primary root elongation, lateral root formation and adventitious root (AR) initiation. Whereas GR24 (a synthetic strigolactone) inhibits LR and AR formation, the effect of SL biosynthesis inhibitor (fluridone) is just the opposite (root proliferation). Naphthylphthalamic acid (NPA) leads to LR proliferation but completely inhibits AR development. The diffusive distribution of PIN1 in the provascular cells in the differentiating zone of the roots in response to GR24, fluridone or NPA treatments further indicates the involvement of localized auxin accumulation in LR development responses. Inhibition of LR formation by GR24 treatment coincides with inhibition of ACC synthase activity. Profuse LR development by fluridone and NPA treatments correlates with enhanced [Ca2+](cyt) in the apical region and differentiating zones of LR, indicating a critical role of [Ca2+] in LR development in response to the coordinated action of auxins, ethylene and SLs. Significant enhancement of carotenoid cleavage dioxygenase (CCD) activity (enzyme responsible for SL biosynthesis) in tissue homogenates in presence of cPTIO (NO scavenger) indicates the role of endogenous NO as a negative modulator of CCD activity. Differences in the spatial distribution of NO in the primary and lateral roots further highlight the involvement of NO in SL-modulated root morphogenesis in sunflower seedlings. Present work provides new report on the negative modulation of SL biosynthesis through modulation of CCD activity by endogenous nitric oxide during SL-modulated LR development.