赤霉素诱导甘蔗节间伸长的cDNA-AFLP差异显示

以‘新台糖22号’甘蔗为材料,在其伸长初期以200mg/L的赤霉素进行叶面喷施处理,对照喷清水,分别提取对照和处理(0、6、12、24h)的总RNA进行等量混合,获得2种不同处理的样品池,采用cDNA-AFLP技术对赤霉素诱导下甘蔗节间伸长的差异表达进行分析。结果显示:(1)通过169对引物组合的选择性扩增,共得到了约11 000条大小在50～700bp的cDNA片段,获得186条差异条带。(2)经反向Northern杂交,于结果显示阳性的TDFs中选取56个片段进行克隆和序列分析,获得56条大小在80～500bp的差异条带。(3)经BLAST分析,按功能可将获得的56条TDFs分为7类,分别为能量与代谢相关基因、未知功能蛋白、未知基因、植物抗性相关基因、细胞壁生物合成与修饰相关基因、信号传导相关基因和转录因子相关基因。该研究获得了一些与甘蔗节间伸长相关的差异基因片段,为进一步研究甘蔗节间伸长的分子机理奠定了基础。     

甘蔗节间伸长过程赤霉素生物合成关键基因的表达及相关植物激素动态变化

以甘蔗(Saccharum officinarum)优良品种桂糖42号(GT42)为研究材料, 分别于未伸长期(9-10叶龄以前) (Ls1)、伸长初期(12-13叶龄) (Ls2)和伸长盛期(15-16叶龄) (Ls3)取甘蔗第2片真叶(自顶部起)对应的节间组织, 测定其赤霉素(GA)、生长素(IAA)、油菜素甾醇(BR)、细胞分裂素(CTK)、乙烯(ETH)和脱落酸(ABA)的含量, 并通过实时荧光定量PCR (qRT-PCR)分析赤霉素合成途径关键基因GA₂₀氧化酶基因(GA20-Oxidase1)、赤霉素受体基因(GID1)和DELLA蛋白编码基因(GAI)的差异表达。结果表明, 在甘蔗伸长期间, GA和IAA含量呈现上升趋势, CTK和ABA含量呈下降趋势, ETH含量先上升后下降, BR含量则变化不明显; GA20-Oxidase1和GID1的表达呈上升趋势, 而GAI的表达则呈下降趋势, 这与相关植物激素的变化基本一致。综上, 甘蔗节间伸长过程主要与GA和IAA相关, 其次为CTK和ABA, 而ETH受到IAA的调控影响节间伸长; 植物激素间通过相互作用调控GA20-Oxidase1、GID1和GAI的表达, 影响GA含量和GA的信号转导过程, 进而影响甘蔗节间的伸长。该研究揭示了甘蔗节间伸长过程中赤霉素生物合成途径和信号转导关键基因的差异表达及植物激素含量的动态变化规律。     

甘蔗节间伸长过程赤霉素生物合成关键基因的表达及相关植物激素动态变化

以甘蔗(Saccharum officinarum)优良品种桂糖42号(GT42)为研究材料, 分别于未伸长期(9-10叶龄以前) (Ls1)、伸长初期(12-13叶龄) (Ls2)和伸长盛期(15-16叶龄) (Ls3)取甘蔗第2片真叶(自顶部起)对应的节间组织, 测定其赤霉素(GA)、生长素(IAA)、油菜素甾醇(BR)、细胞分裂素(CTK)、乙烯(ETH)和脱落酸(ABA)的含量, 并通过实时荧光定量PCR (qRT-PCR)分析赤霉素合成途径关键基因GA₂₀氧化酶基因(GA20-Oxidase1)、赤霉素受体基因(GID1)和DELLA蛋白编码基因(GAI)的差异表达。结果表明, 在甘蔗伸长期间, GA和IAA含量呈现上升趋势, CTK和ABA含量呈下降趋势, ETH含量先上升后下降, BR含量则变化不明显; GA20-Oxidase1和GID1的表达呈上升趋势, 而GAI的表达则呈下降趋势, 这与相关植物激素的变化基本一致。综上, 甘蔗节间伸长过程主要与GA和IAA相关, 其次为CTK和ABA, 而ETH受到IAA的调控影响节间伸长; 植物激素间通过相互作用调控GA20-Oxidase1、GID1和GAI的表达, 影响GA含量和GA的信号转导过程, 进而影响甘蔗节间的伸长。该研究揭示了甘蔗节间伸长过程中赤霉素生物合成途径和信号转导关键基因的差异表达及植物激素含量的动态变化规律。     

陆地棉与海岛棉纤维细胞伸长中过氧化物酶活性比较

陆地棉中棉所１２号的棉纤维细胞在开花后２５ｄ而海岛棉８７６３依则在开花后３６ｄ停止伸长。两者纤维中可溶性蛋白与纤维伸长的关系不大。过氧化物酶的活性升高的前者对纤维伸长有一定的抑制作用,而与后者关系不明显,两者纤维中离子结合型胞壁蛋白含量与ＰＯＤ活性,皆在纤维细胞伸长停止期出现高峰。     

陆地棉与海岛棉纤维细胞伸长中过氧化物酶活性比较(简报)

陆地棉中棉所12号的棉纤维细胞在开花后25d而海岛棉8763依则在开花后36d停止伸长。两者纤维中可溶性蛋白与纤维伸长的关系不大。过氧化物酶（POD）的活性升高对前者纤维伸长有一定的抑制作用,而与后者关系不明显。两者纤维中离子结合型胞壁蛋白含量与POD活性,皆在纤维细胞伸长停止期出现高峰。     

甘蔗节间蔗糖含量与和蔗糖代谢相关的4种酶活性之间的关系剖析

测定和分析2个品种甘蔗节间蔗糖含量与和蔗糖代谢相关的4种酶活性之间关系的结果表明:节间蔗糖含量与酸性转化酶活性成极显著负相关,与蔗糖磷酸合成酶活性呈显著正相关。从通径分析结果可知,4种关键酶中可溶性酸性转化酶和蔗糖磷酸合成酶是对蔗糖含量贡献程度最大的2个酶.     

深水稻节间伸长生长的机制

淹水可促进深水稻节间快速伸长生长,其主要受内源赤霉素、乙烯、脱落酸等激素信号分子的调控。淹水能促进深水稻植株体内乙烯、赤霉素的生物合成、抑制脱落酸的生物合成,外源乙烯、赤霉素会加速深水稻节间伸长,而外源脱落酸抑制淹水节间的伸长,其中赤霉素是直接作用因子,乙烯能降低内源脱落酸水平、增加节间对赤霉素的敏感性;还与渗透调节、细胞壁组份如膨胀素等有关,淹水及赤霉素都大大增加了膨胀素基因的表达。并就深水稻的进一步研究进行了展望。     

麻竹节间伸长过程的初步研究

竹子秆茎的快速生长是禾本科生物学的一个未解之谜,而秆茎的生长又是以节间为单位进行的。本研究以第8节为标准节,利用统计学及石蜡切片的方法,获得了麻竹的节间伸长曲线以及节间组织发育的形态解剖信息。麻竹节间的伸长呈现“慢-快”的生长趋势,早期节间以细胞分裂为主,然后节间由上到下逐渐进入细胞伸长阶段,最后节间停止伸长进入成熟生长阶段。本研究为大型丛生竹节间发育的研究提供了基础数据,有助于推动对竹子笋株快速生长机制的研究。     

棉纤维细胞伸长生长与过氧化物酶和IAA氧化酶的关系

棉纤维细胞于开花当天从棉胚珠表皮上发生,随即开始伸长生长,星S型生长曲线。棉纤维细胞的可溶性蛋白、过氧化物酶活性和IAA氧化酶活性同伸长生长的关系不大;而离子型结合的细胞壁蛋白质含量、过氧化物酶活性和IAA氧化酶活性同棉纤维细胞的伸长生长关系较大,表现在棉纤维细胞快速伸长期活性较低,而在伸长生长停止时出现活性高峰,同棉纤维细胞的伸长生长有负相关现象。     

外源精胺对小麦幼苗抗氧化酶活性的促进作用

外源精胺（Spm）降低了离体小麦叶片衰老时MDA的含量,且降低程度与精胺的浓度成正比。0.2mmol/L的精胺提高了小麦幼苗体内的超氧化物歧化酶（SOD）,过氧化氢酶（CAT）,过氧化物酶（POD）及抗坏血酸过氧化物酶（ASP）的活性。体内及体外试验表明精胺既可诱导SOD与POD的合成,又可直接作用于酶分子上以提高酶的活性;精胺对CAT合成仅能诱导,对已有酶活性无调节作用;精胺对ASP的合成无影响,却能促进已有酶的活性。     

Internode length in Pisum. Two further gibberellin-insensitivity genes, lka and lkb

Two further internode length genes are identified in Pisum sativum L. and named lka (identified from line NGB5865) and lkb (from NGB5862). These genes result in a similar phenotype, which includes reduced stem elongation, peduncle length and basal branching, and 'banding' of the stem. These effects are similar to, but less severe than, those of gene lk . Genes lka and lkb influence gibberellin (GA) sensitivity, since mutants NGB5865 and NGB5862 possess similar levels of endogenous GA-like substances to the wild-type parental cultivar Torsdag and respond less to applied GA₁ than do wild-type plants or GA-synthesis mutants of a similar stature. The action of genes lka and lkb is localised in the young apical tissue but is not thought to involve GA-perception, since plants possessing genes lka and lkb are not true phenocopies of GA-deficient plants. The genetic interaction of genes lka and lkb is examined and the action of gene lkb on a le gene background determined.     

Internode length in Pisum. Biochemical expression of the le gene in darkness

Ross, J. J. and Reid, J. B. 1989. Internode length in Pisum. Biochemical expression of the Le gene in darkness.
The Le gene appears to be biochemically expressed in dark-grown pea ( Pisum sativum L.) plants since the previously reported difference in metabolism of [³H]-GA₃₀ between light-grown Le and Le plants was also observed in darkness. Furthermore, both light- and dark-grown Le plants contained more endogenous GA¹, -like substance than did comparable Le plants. Darkness did not appear to significantly increase the accumulation of GA¹, in either Le or Le plants, although confirmation of GA¹ levels by gas chromatography-selected ion monitoring is still required. The results support previous findings that the overall metabolism of [³H]-GA₂₀, is accelerated by darkness. The evidence presented here supports previous suggestions that darkness acts on internode length by increasing some aspect of GA sensitivity.     

Internode length in Pisum. Action of gene lw

Jolly, C. J., Reid, J. B. and Ross, J. J. 1987. Internode length in Pisum. Action of gene lw.
Mutant K29 of Pisum sativum L. is shown to possess a recessive gene at a new locus, lw , which results in reduced internode length, delayed flowering and increased symptoms of water congestion compared with the parental cv. Torsdag. The interaction of gene lw with the internode length genes na, le, la and cry ⁵ is examined. Extracts from the shoots of Iw plants are shown to contain similar levels of gibberellin (GA)-like substances to comparable Lw plants, but Iw plants do not elongate to the same extent as Lw plants when treated with GA₁₉ GA₁₉, or GA₂₀. The effect of gene Iw is not graft-transmissible. Unlike essentially isogenic dwarf lines possessing the GA-synthesis genes le, Ih or Is, lw plants show a relative increase in elongation similar to Torsdag in response to photoperiod extensions from sources rich in far-red light. These results suggest that gene lw probably does not reduce elongation by influencing GA-synthesis and that the response to photoperiod extensions with far-red light may depend on the level of GA.     

Internode length in Pisum. The involvement of ethylene with the gibberellin-insensitive erectoides phenotype

The gene lk in peas ( Pisum sativum L.) confers the erectoides phenotype. This phenotype possesses much reduced internode and petiole lengths and is practically insensitive to applied GA₁, compared with Lk plants. Application of the ethylene synthesis inhibitor, aminoethoxyvinylglycine (AVG), resulted in increased internode elongation and increased GA-sensitivity in lk plants, but not in the Lk line, L53. The ethylene-releasing compound, ethephon, had the reverse effect when applied to the Lk line, L58, reducing internode length and GA-sensitivity. Ethylene production was higher in lk segregates than in Lk segregates under the conditions used, and the shoot anatomy of lk segregates was consistent with these higher ethylene levels.
These results suggest that the phenotypic effects of gene lk may be due, at least in part, to increased ethylene production in erectoides plants. However, AVG application to lk plants did not produce true phenocopies of comparable lk plants and ethephon application to Lk plants did not produce the erectoides phenotype. Further work is therefore required to determine whether the effect of the gene lk on ethylene production is the primary action of this gene or merely a secondary consequence.     

Gibberellin-induced ethylene production and its effect on cowpea epicotyl elongation

The effect of gibberellin A₁ (GA₁) on production of ethylene by cowpea (Vigna sinensis cv Blackeye pea no. 5) epicotyl explants and its relationship to epicotyl elongation was investigated. The explants were placed upright in water and incubated in sealed culture tubes or in large jars. GA, and IAA in ethanol solution were injected into the subapical tissues of the decapitated epicotyls. Cowpea epicotyl explants elongated after GA but not after IAA treatment, and they were very sensitive to exogenous ethylene. As little as 0.14 1/1 ethylene reduced significantly GA₁-induced epicotyl elongation.Treatment with GA₁ induced the production of ethylene which began 10 h after GA application, showed a peak at about 22 h and then declined. The yield of ethylene was proportional to the amount of GA, injected. The inhibition of epicotyl elongation in closed tubes was avoided by absorbing ethylene released with Hg(Cl0₄)₂ , or by adding AVG to the incubation solution to inhibit ethylene production. Treatment with IAA elicited a rapid production of ethylene which ceased about 10 h after application. The effects of IAA and GA₁ on ethylene production were additive.Abbreviations AVG aminoethoxyvinylglycine 2-amino-4-(2-aminoethoxy)-trans-3butenoic acid - ACC 1-aminocyclopropane-1-carboxylic acid - GA gibberellin - IAA indole-3-acetic acid     

Internode length in Pisum. Two further mutants, lh and ls, with reduced gibberellin synthesis, and a gibberellin insensitive mutant, lk

Three further internode length mutants in peas ( Pisum sativum L.), lh , ls and lk , were examined to determine if they influenced gibberellin synthesis or sensitivity. Two mutants, lh and ls , showed pronounced elongation in response to applied GA₁ and extracts from their shoots contained little gibberellin-like activity when assayed on the rice seedling (cv. Tan ginbozu) bioassay compared with similar extracts from essentially isogenic Lh and Ls plants. The third mutant, lk , was almost insensitive to applied GA₁ and at no dose rate did it become a phenocopy of normal Lk plants. Extracts from the shoots of lk and Lk segregants contained similar levels of gibberellinlike substances. All three mutants influenced growth in both the light and the dark, although only the effect of genes Lh and Ls were graft transmissible. These results suggest that lh and ls are mutants with reduced gibberellin synthesis, while lk is the first gibberellin-insensitive dwarfing gene identified in peas.     

Internode length in Pisum. Estimation of GA1 levels in genotypes Le, le and led

The levels of GA₁, 3-epiGA₁ and GA₈ in genotypes Le, le and le^d of Pisum sativum L. were determined by gas chromatography-selected ion monitoring (GC-SIM) after feeds of [³H, ¹³C]-GA₂₀ to each genotype. The levels of endogenous and [¹³C]-labelled metabolites were determined by reverse isotope dilution with unlabelled GA₁, 3-epiGA₁ and GA₈. The results demonstrate a quantitative relationship between the level of GA₁ and the extent of elongation both on a per plant and a per g fresh weight basis. These results are consistent with previous findings in peas and other species possessing a predominant early 13-hydroxylation pathway for GA biosynthesis.
The levels of 3-epiGA₁ also decreased in the genotypic sequence Le, le, le^d although not as rapidly as for the level of GA₁. This may suggest that the alleles at the le locus also influence the formation of 3-epiGA₁.