Fruitlet calyx shedding in pear plants is apparently regulated via numerous pathways that involve both environmental triggers and phytohormones cues such as auxin. In this study, we found at 10 days after full bloom (...Fruitlet calyx shedding in pear plants is apparently regulated via numerous pathways that involve both environmental triggers and phytohormones cues such as auxin. In this study, we found at 10 days after full bloom (DAFB) higher levels of indoleacetic acid (IAA) and tryptophan (Trp) in calyx persistence fruitlet (CPF) than calyx shedding fruitlet (CSF) ofDanshan Suli’ pear (Pyrus bretschneideri Rhed.). Consisting with this, the activity of indolealdehyde oxidase (IAAIdO), which promotes IAA synthesis, was remarkably increased, and that of peroxidase(POD), which degrades IAA, dropped markedly in CPF but not in CSF. Further, qRT-PCR results revealed that most of 31 PbrARFs (encoding auxin response factors) in Pyrus bretschneideri were highly expressed in CPF, whereas PbrARF4, PbrARF24 and PbrARF26 were significantly downregulated in CPF vis-a-vis CSF. Phylogenetic analysis revealed that 6 PbrARFs clustered in the group III, where PbrARF4 showed the closest affinity with AtARF1 that promotes organ abscission, indicating a putative role of PbrARF4 in mediating the process of calyx shedding in pear. In fact, the ectopic overexpression of PbrARF4 in Solanum lycopersicum resulted in an earlier-formed and deeper abscission layer (AL) in the transgenic plants, whose calyxes were more prone to wilt at the mature red stage (MR) compared with the control plants (wild-type). More importantly, expression levels of the abscission genes SILS and Sl Cel2 in transgenic plants overexpressing PbrARF4 were significantly upregulated in comparation with the WT, whereas those of Sl BI and Sl TAPG2 were considerably inhibited. Further, PbrJOINTLESS and PbrIDA,the two genes related to calyx shedding in pear, were up-regulated more in CSF than CPF. The findings contribute to a better understanding of PbrARFs involved in fruitlet calyx shedding of pear, which could prove beneficial to improving the quality of pear fruit.展开更多
In order to improve the management of nitrogen(N) fertilization in pear orchards, we investigated the effects of application timing on the distribution, storage, and remobilization of N in mature pear trees in a field...In order to improve the management of nitrogen(N) fertilization in pear orchards, we investigated the effects of application timing on the distribution, storage, and remobilization of N in mature pear trees in a field experiment at Jingtai County, Gansu Province, China. Nine trees were selected for the experiment and each received equal aliquots of 83.33 g N in the autumn, spring, and summer, with ^(15)N-labeled(NH_4)_2SO_4 used in one of the aliquots each season. Results showed that the(^(15)NH_4)_2SO_4 applied in the autumn remained in the soil during the winter. In the following spring this N was absorbed and rapidly remobilized into each organ, especially new organs(leaves, fruit and new shoots). The ^(15)N supplied in spring was rapidly transported to developing fruit between the young fruit and fruit enlargement stages. ^(15)N from the summer application of fertilizer was mainly stored in the coarse roots over the winter, then was mobilized to support growth of new organs in spring. In conclusion, for pear trees we recommend that the autumn application of N-fertilizer be soon after fruit harvest in order to increase N stores in fine roots. Spring application should be between full bloom and the young fruit stages to meet the high N demands of developing fruit. Summer application of fertilizer at the fruit enlargement stage does not contemporaneously affect the growth of pears, but increases the N stored in coarse roots, and in turn the amount available for remobilization in spring.展开更多
【目的】从鸭梨果实中克隆Pb Chi IV的全长c DNA序列,检测Pb Chi IV在根、茎、叶、果实以及在水杨酸(SA)和梨轮纹病菌诱导下的表达特性,以探讨该基因与SA信号转导及抗梨轮纹病菌的相关性。【方法】设计特异引物,克隆Pb Chi IV的全长序列...【目的】从鸭梨果实中克隆Pb Chi IV的全长c DNA序列,检测Pb Chi IV在根、茎、叶、果实以及在水杨酸(SA)和梨轮纹病菌诱导下的表达特性,以探讨该基因与SA信号转导及抗梨轮纹病菌的相关性。【方法】设计特异引物,克隆Pb Chi IV的全长序列,将测序得到的核苷酸序列和推导的氨基酸序列在NCBI上用BLAST进行序列相似性分析,利用Biot Edit软件对氨基酸序列进行比对,利用MEGA6.0构建系统发育树,利用实时荧光定量PCR技术分析该基因在梨不同组织以及在SA和梨轮纹病菌诱导下的表达。【结果】克隆了Pb Chi IV的c DNA序列为819 bp,Gen Bank数据库登录号为KJ872676。生物信息学分析表明,Pb Chi IV编码272个氨基酸,与沙梨的同源性达100%,与毛果杨(XP_006376418.1)、葡萄(NP001268173.1)、拟南芥(CAA74930.1)、紫花苜蓿(ACL36992.1)、蒺藜苜蓿(AAR87869.1)、豇豆(CAA61281.1)、榛子(AEM97876.1)、东方山羊豆(AAP03085.1)、葡萄(NP_001268075.1)、华东葡萄(ABY66958.1)、葡萄(AAB65777.1)、烟草(BAF44533.1)和海岛棉(AER29902.1)的同源性分别为79%、73%、73%、72%、72%、72%、69%、68%、67%、67%、65%、67%和62%,属于第IV类几丁质酶基因。表达分析表明,Pb Chi IV在根中的表达量最大,分别是茎和叶的4.32和2.96倍,其次是在果实中的表达量,分别是茎和叶的2.48和1.70倍,在叶片和茎中的表达相对较低。在鸭梨幼果和成熟期果实中,SA和梨轮纹病菌均可诱导该基因表达。SA处理后基因的最大表达量是对照的2.83和3.8倍,病原菌处理后基因的最大表达量是对照的1.82和1.66倍,SA、病原菌处理后基因的最大表达量是对照的2.49和3.43倍,表达量分别在72、24和72 h达到最大值。【结论】Pb Chi IV可能参与SA介导的植物抗病防卫反应的信号通路,推测其参与梨轮纹病菌引起的防卫反应,在鸭梨抗病过程中起作用。展开更多
基金supported by the China Agriculture Research System (Grant No.CARS-28-14)。
文摘Fruitlet calyx shedding in pear plants is apparently regulated via numerous pathways that involve both environmental triggers and phytohormones cues such as auxin. In this study, we found at 10 days after full bloom (DAFB) higher levels of indoleacetic acid (IAA) and tryptophan (Trp) in calyx persistence fruitlet (CPF) than calyx shedding fruitlet (CSF) ofDanshan Suli’ pear (Pyrus bretschneideri Rhed.). Consisting with this, the activity of indolealdehyde oxidase (IAAIdO), which promotes IAA synthesis, was remarkably increased, and that of peroxidase(POD), which degrades IAA, dropped markedly in CPF but not in CSF. Further, qRT-PCR results revealed that most of 31 PbrARFs (encoding auxin response factors) in Pyrus bretschneideri were highly expressed in CPF, whereas PbrARF4, PbrARF24 and PbrARF26 were significantly downregulated in CPF vis-a-vis CSF. Phylogenetic analysis revealed that 6 PbrARFs clustered in the group III, where PbrARF4 showed the closest affinity with AtARF1 that promotes organ abscission, indicating a putative role of PbrARF4 in mediating the process of calyx shedding in pear. In fact, the ectopic overexpression of PbrARF4 in Solanum lycopersicum resulted in an earlier-formed and deeper abscission layer (AL) in the transgenic plants, whose calyxes were more prone to wilt at the mature red stage (MR) compared with the control plants (wild-type). More importantly, expression levels of the abscission genes SILS and Sl Cel2 in transgenic plants overexpressing PbrARF4 were significantly upregulated in comparation with the WT, whereas those of Sl BI and Sl TAPG2 were considerably inhibited. Further, PbrJOINTLESS and PbrIDA,the two genes related to calyx shedding in pear, were up-regulated more in CSF than CPF. The findings contribute to a better understanding of PbrARFs involved in fruitlet calyx shedding of pear, which could prove beneficial to improving the quality of pear fruit.
基金funded by the earmarked fund of China Agriculture Research System(CARS-29-10)。
文摘In order to improve the management of nitrogen(N) fertilization in pear orchards, we investigated the effects of application timing on the distribution, storage, and remobilization of N in mature pear trees in a field experiment at Jingtai County, Gansu Province, China. Nine trees were selected for the experiment and each received equal aliquots of 83.33 g N in the autumn, spring, and summer, with ^(15)N-labeled(NH_4)_2SO_4 used in one of the aliquots each season. Results showed that the(^(15)NH_4)_2SO_4 applied in the autumn remained in the soil during the winter. In the following spring this N was absorbed and rapidly remobilized into each organ, especially new organs(leaves, fruit and new shoots). The ^(15)N supplied in spring was rapidly transported to developing fruit between the young fruit and fruit enlargement stages. ^(15)N from the summer application of fertilizer was mainly stored in the coarse roots over the winter, then was mobilized to support growth of new organs in spring. In conclusion, for pear trees we recommend that the autumn application of N-fertilizer be soon after fruit harvest in order to increase N stores in fine roots. Spring application should be between full bloom and the young fruit stages to meet the high N demands of developing fruit. Summer application of fertilizer at the fruit enlargement stage does not contemporaneously affect the growth of pears, but increases the N stored in coarse roots, and in turn the amount available for remobilization in spring.
文摘【目的】从鸭梨果实中克隆Pb Chi IV的全长c DNA序列,检测Pb Chi IV在根、茎、叶、果实以及在水杨酸(SA)和梨轮纹病菌诱导下的表达特性,以探讨该基因与SA信号转导及抗梨轮纹病菌的相关性。【方法】设计特异引物,克隆Pb Chi IV的全长序列,将测序得到的核苷酸序列和推导的氨基酸序列在NCBI上用BLAST进行序列相似性分析,利用Biot Edit软件对氨基酸序列进行比对,利用MEGA6.0构建系统发育树,利用实时荧光定量PCR技术分析该基因在梨不同组织以及在SA和梨轮纹病菌诱导下的表达。【结果】克隆了Pb Chi IV的c DNA序列为819 bp,Gen Bank数据库登录号为KJ872676。生物信息学分析表明,Pb Chi IV编码272个氨基酸,与沙梨的同源性达100%,与毛果杨(XP_006376418.1)、葡萄(NP001268173.1)、拟南芥(CAA74930.1)、紫花苜蓿(ACL36992.1)、蒺藜苜蓿(AAR87869.1)、豇豆(CAA61281.1)、榛子(AEM97876.1)、东方山羊豆(AAP03085.1)、葡萄(NP_001268075.1)、华东葡萄(ABY66958.1)、葡萄(AAB65777.1)、烟草(BAF44533.1)和海岛棉(AER29902.1)的同源性分别为79%、73%、73%、72%、72%、72%、69%、68%、67%、67%、65%、67%和62%,属于第IV类几丁质酶基因。表达分析表明,Pb Chi IV在根中的表达量最大,分别是茎和叶的4.32和2.96倍,其次是在果实中的表达量,分别是茎和叶的2.48和1.70倍,在叶片和茎中的表达相对较低。在鸭梨幼果和成熟期果实中,SA和梨轮纹病菌均可诱导该基因表达。SA处理后基因的最大表达量是对照的2.83和3.8倍,病原菌处理后基因的最大表达量是对照的1.82和1.66倍,SA、病原菌处理后基因的最大表达量是对照的2.49和3.43倍,表达量分别在72、24和72 h达到最大值。【结论】Pb Chi IV可能参与SA介导的植物抗病防卫反应的信号通路,推测其参与梨轮纹病菌引起的防卫反应,在鸭梨抗病过程中起作用。
