Hormonal and stress induction of the gene encoding common bean acetyl-coenzyme A carboxylase

Regulation of the cytosolic acetyl-coenzyme A carboxylase (ACCase) gene promoter from common bean (Phaseolus vulgaris) was studied in transgenic Arabidopsis (Arabidopsis thaliana) plants using a beta-glucuronidase (GUS) reporter gene fusion (PvACCase::GUS). Under normal growth conditions, GUS was expressed in hydathodes, stipules, trichome bases, flowers, pollen, and embryos. In roots, expression was observed in the tip, elongation zone, hypocotyl-root transition zone, and lateral root primordia. The PvACCase promoter was induced by wounding, Pseudomonas syringae infection, hydrogen peroxide, jasmonic acid (JA), ethylene, or auxin treatment. Analysis of PvACCase::GUS expression in JA and ethylene mutants (coronatine insensitive1-1 [coi1-1], ethylene resistant1-1 [etr1-1], coi1-1/etr1-1) suggests that neither JA nor ethylene perception participates in the activation of this gene in response to wounding, although each of these independent signaling pathways is sufficient for pathogen or hydrogen peroxide-induced PvACCase gene expression. We propose a model involving different pathways of PvACCase gene activation in response to stress.     

伤处理和乙烯对桃ACC氧化酶基因表达的影响

桃果实不耐贮运,特别是溶质水蜜桃、珐I大11＿程技术的发展使番茄果实实现延熟保鲜'－'、人f［］也试图通过乙烯合成的关键酶的］i义HNA技术来延长桃果实的贮运期。：ICC氧化酶是乙烯生物合成的关键酶之一,ACC氧化酶4peJL从番茄'、矮牵牛。。。桃卜'、苹果、'等许多植物...     

Pistil-Specific and Ethylene-Regulated Expression of 1-Aminocyclopropane-1-Carboxylate Oxidase Genes in Petunia Flowers

The differential expression of the petunia 1-aminocyclopropane-1-carboxylate (ACC) oxidase gene family during flower development and senescence was investigated. ACC oxidase catalyzes the conversion of ACC to ethylene. The increase in ethylene production by petunia corollas during senescence was preceded by increased ACC oxidase mRNA and enzyme activity. Treatment of flowers with ethylene led to an increase in ethylene production, ACC oxidase mRNA, and ACC oxidase activity in corollas. In contrast, leaves did not exhibit increased ethylene production or ACC oxidase expression in response to ethylene. Gene-specific probes revealed that the ACO1 gene was expressed specifically in senescing corollas and in other floral organs following exposure to ethylene. The ACO3 and ACO4 genes were specifically expressed in developing pistil tissue. In situ hybridization experiments revealed that ACC oxidase mRNAs were specifically localized to the secretory cells of the stigma and the connective tissue of the receptacle, including the nectaries. Treatment of flower buds with ethylene led to patterns of ACC oxidase gene expression spatially distinct from the patterns observed during development. The timing and tissue specificity of ACC oxidase expression during pistil development were paralleled by physiological processes associated with reproduction, including nectar secretion, accumulation of stigmatic exudate, and development of the self-incompatible response.     

Regulation of Expression of the prb-1b / ACC Deaminase Gene by UV-8 in Transgenic Tomatoes

Transgenic tomato plants with 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase gene from Enterobacter cloacae UW4 under the control of a pathogenesis-related promoter (prb-1b) from tobacco were challenged by abiotic stresses to determine the expression patterns ofthe transgene. No ACC deaminase RNA or protein was detected by RT-PCR and in western blots prepared from leaf proteins of transgenic plants after wounding or treatment with α-amino butyric acid, xylanase, ethephon, salicylic acid, jasmonic acid, ethylene, or ethylene plus jasmonic acid. However, expression of the ACC deaminase transgene was observed in leaves and roots oftransformed tomato lines exposed to UV light. The UV response required a minimum of 48 h of exposure and was specific to UV-8 light.     

Differential expression of antisense in regenerated tobacco plants transformed with an antisense version of a tomato ACC oxidase gene

Ethylene production was measured during vegetative and reproductive development in normal tobacco plants and in transgenic tobacco plants carrying antisense genes for tomato ACC oxidase driven by the 35S CaMV promoter (Hamilton et al., 1990). When expressed in three independently derived transgenic plants, the antisense ethylene gene failed to affect ethylene production in young/mature leaves or in stems but it did inhibit ethylene production in roots by 37–58%. Ethylene production in developing flowers (i.e. from small unopened flower buds up until open flowers at anthesis) was not affected in transgenic plants but ethylene production in fruits was inhibited by 35%. The most dramatic effect on ethylene production in transgenic plants was seen immediately after wounding leaf tissue, in which case the antisense gene inhibited wound ethylene production by 72%. Thus, the antisense gene composed of a 35S CaMV promoter driving a heterologous ACC oxidase sequence had differential effects on ethylene production in tobacco plants.     

ACC氧化酶和ACC合成酶反义RNA融合基因导入番茄和乙烯合成的抑制

从番茄品种强力米寿的总DNA中克隆番茄果实特异启动子2A11,以番茄成熟果实的RNA为模板,进行RT-PCR扩增,克隆番茄全长的ACC氧化酶基因和ACC合成酶基因片段。完成两个基因的克隆和测序后,将888bp的番茄ACC氧化酶基因和943bp的ACC合成酶基因片段串联,构成全长1837bp的融合基因。将该融合基因以反义的方向插入植物双元载体pYPX145中番茄果实表达特异启动子下游,获得ACC氧化酶基因和ACC合成酶基因融合的植物双元载体pOSACC。该载体外源基因表达单元的两端含两个烟草SAR序列,利于转基因的稳定遗传。以番茄栽培品种合作903子叶和下胚轴为外植体,利用根癌农杆菌进行基因转化,通过200mg／L卡那霉素选择和GUS检测,获得了105株番茄GUS阳性植株,转基因番茄果实在当代表现明显耐贮特点。经过4代的耐贮和果实农艺性状的综合选择,获得了两个表现良好的株系DR-1和DR-2,两株系果实乙烯释放量显著下降,是未转基因材料的9．5％,番茄的贮存期在50天以上。     

高羊茅FaChit1基因启动子的功能分析

用含有不同长度FaChitl基因启动子区域与GUS基因融合构建植物表达载体pFaChitlP—I、pFaChitlP-Ⅱ以及pFaChitlP-Ⅲ并分别对烟草进行转化,经真菌激发子、干旱、机械损伤以及乙烯等多种胁迫处理后测定GUS活性。启动子缺失分析实验结果显示,真菌激发子对FaChitl基因启动子所介导的GUS诱导表达效果最强,而机械损伤只能微弱地诱导GL靥基因表达;FaChitl基因启动子-651bp以内的序列均能介导GUS基因的诱导表达,同时-935bp与-233bp之间的区域是该启动子响应真菌激发子、乙烯以及机械损伤胁迫所必需的。表明FaChitl启动子是一个多胁迫诱导型启动子。     

ACC氧化酶和ACC合成酶反义RNA融合基因导入番茄和乙烯合成的抑制

从番茄品种强力米寿的总DNA中克隆番茄果实特异启动子2A11,以番茄成熟果实的RNA为模板,进行RT-PCR扩增,克隆番茄全长的ACC氧化酶基因和ACC合成酶基因片段。完成两个基因的克隆和测序后,将888bp的番茄ACC氧化酶基因和943bp的ACC合成酶基因片段串联,构成全长1837bp的融合基因。将该融合基因以反义的方向插入植物双元载体pYPX145中番茄果实表达特异启动子下游,获得ACC氧化酶基因和ACC合成酶基因融合的植物双元载体pOSACC。该载体外源基因表达单元的两端含两个烟草SAR序列,利于转基因的稳定遗传。以番茄栽培品种合作903子叶和下胚轴为外植体,利用根癌农杆菌进行基因转化,通过200mg/L卡那霉素选择和GUS检测,获得了105株番茄GUS阳性植株,转基因番茄果实在当代表现明显耐贮特点。经过4代的耐贮和果实农艺性状的综合选择,获得了两个表现良好的株系DR-1和DR-2,两株系果实乙烯释放量显著下降,是未转基因材料的9.5%,番茄的贮存期在50天以上。     

LE-ACS6启动子在LE-ACS6::GUS转基因拟南芥中的特异性

通过对不同发育时期LE-ACS6::GUS转基因拟南芥中GUS表达特异性的研究,证明LE-ACS6基因的启动子在拟南芥中也表现启动参与第一系统乙烯合成的关键酶基因的活性.在转基因拟南芥中,LE-ACS6启动子还表现响应外源生长素处理、伤害处理等多种刺激因子的特点.     

Expression of ACC synthase is enhanced earlier than that of ACC oxidase during fruit ripening of mume (Prunus mume)

Mume (Japanese apricot: Prunus mume Sieb. et Zucc.) is a climacteric fruit that produces large amounts of ethylene as it ripens. Ripening is accompanied by marked increases in the activities of two ethylene-biosynthetic enzymes, namely, 1-aminocyclopropane-1-carboxylic acid (ACC) synthase and ACC oxidase. To study the molecular aspects of ripening of mume, we isolated cDNA clones for proteins that we considered likely to be involved in the biosynthesis and perception of ethylene during ripening, namely, ACC synthase, ACC oxidase and the ethylene receptor. Northern blotting analysis revealed the markedly increased expression of ACC synthase prior to that of ACC oxidase and the increase in ethylene production during ripening. Overall, the levels of the mRNAs for the genes corresponded closely to the levels of activity of the ethylene-biosynthetic enzymes. Exposure of mature green mume fruit to ethylene for 12 h induced strong expression of ACC synthase, as well as of ACC oxidase. Wounding of the pericarp of mume fruit induced the expression of ACC synthase but not of ACC oxidase. The rate of ethylene production increased only slightly after wounding. These results suggest that expression of the genes for ACC synthase and ACC oxidase must be activated sequentially for maximum production of ethylene during ripening of mume fruit and that several mechanisms regulate the expression of ethylene-biosynthetic genes during ripening.