Fertility analysis of the Arabidopsis transformed with antisense rice osRACD gene

The full length osRACD cDNA sequence was subcloned into the pBI121 plasmid in the antisense orientation under the control of the CaMV35S promoter to construct the expression vector pBID, and the constructs were introduced into Arabidopsis plants by using the vacuum infiltration method. The siliques of the transformants stopped growing after anthesis, and they turned yellow or died later; and the siliques from the control plants transformed by the pBI continued growing after anthesis and matured normally. In vitro pollen germination demonstrated that the growth and elongation process of the pollens of the transgenic plants was inhibited, the pollen tubes were shorter and slightly fatter than the tubes of the control plants, which grew normally with long cyclindrical tubes. The above results suggest the function of osRACD gene involved in regulation of the growth and elongation process of pollen tube, its encoding protein may be one of the important factors in regulation of fertility transition of the photoperiod-sensitive genic male-sterile rice Nongken 58S.     

硫氧还蛋白f介导的烟草Rubisco活化酶的氧化还原调控

利用菠菜和烟草的硫氧还蛋白f(Trx-f)在不同氧化还原状态下测定了菠菜、拟南芥、烟草和番茄Rubisco活化酶(RCA)活化其Rubisco的活力,实验结果显示菠菜Trx-f只能介导调控菠菜和拟南芥RCA的氧化还原状态,从而改变其活力,而烟草Trx-f介导也只能改变烟草和番茄RCA的氧化还原状态.上述结果表明烟草等物种的单亚型RCA也能受Trx-f介导的氧化还原调控,而且Trx-f介导的RCA氧化还原状态的改变具有种属专一性.     

Structure and function of the AAA+ protein CbbX, a red-type Rubisco activase

Ribulose 1,5-bisphosphate carboxylase/oxygenase (Rubisco) catalyses the fixation of atmospheric CO(2) in photosynthesis, but tends to form inactive complexes with its substrate ribulose 1,5-bisphosphate (RuBP). In plants, Rubisco is reactivated by the AAA(+) (ATPases associated with various cellular activities) protein Rubisco activase (Rca), but no such protein is known for the Rubisco of red algae. Here we identify the protein CbbX as an activase of red-type Rubisco. The 3.0-? crystal structure of unassembled CbbX from Rhodobacter sphaeroides revealed an AAA(+) protein architecture. Electron microscopy and biochemical analysis showed that ATP and RuBP must bind to convert CbbX into functionally active, hexameric rings. The CbbX ATPase is strongly stimulated by RuBP and Rubisco. Mutational analysis suggests that CbbX functions by transiently pulling the carboxy-terminal peptide of the Rubisco large subunit into the hexamer pore, resulting in the release of the inhibitory RuBP. Understanding Rubisco activation may facilitate efforts to improve CO(2) uptake and biomass production by photosynthetic organisms.     

Introduction of antisense waxy gene into main parent lines of indica hybrid rice

Amylose content in rice endosperm is one of thekey determinants of rice eating and cooking quality, and thepoor quality of indica hybrid rice is closely related to thehigh amylose level in rice grains. In order to improve thegrain quality of the indica hybrid rice by genetic engineering,an antisense fragment of rice waxy gene, driven by theintroduced into three major parent lines of indica hybrid rice,all contain a high amylose level in the grains, via Agrobacte-rium, and more than 100 hygromycin-resistant plants wereregenerated. The analysis of PCR amplification and South-ern blots indicated that the T-DNA containing the antisensewaxy gene had been integrated into the genome of transgenicrice plants. Most of the primary transgenic rice plants grewnormally, and the mature seeds from these transgenic plantswere performed for analysis of the amylose content. Theresults showed that the amylose content in the endosperm ofsome grains was reduced and the lowest reached 7.02% inone homozygous transgenic line, 72.4% lower than that ofthe wild type. The influence of the altered amylose contenton the gelatinization temperature and gel consistency wasalso observed in several homozygous transgenic rice plants.     

Characteristics of C4 photosynthesis in stems and petioles of C3 flowering plants.

Most plants are known as C3 plants because the first product of photosynthetic CO2 fixation is a three-carbon compound. C4 plants, which use an alternative pathway in which the first product is a four-carbon compound, have evolved independently many times and are found in at least 18 families. In addition to differences in their biochemistry, photosynthetic organs of C4 plants show alterations in their anatomy and ultrastructure. Little is known about whether the biochemical or anatomical characteristics of C4 photosynthesis evolved first. Here we report that tobacco, a typical C3 plant, shows characteristics of C4 photosynthesis in cells of stems and petioles that surround the xylem and phloem, and that these cells are supplied with carbon for photosynthesis from the vascular system and not from stomata. These photosynthetic cells possess high activities of enzymes characteristic of C4 photosynthesis, which allow the decarboxylation of four-carbon organic acids from the xylem and phloem, thus releasing CO2 for photosynthesis. These biochemical characteristics of C4 photosynthesis in cells around the vascular bundles of stems of C3 plants might explain why C4 photosynthesis has evolved independently many times.     

bar基因表达框和完整质粒转化对水稻农艺性状的变异效应比较

通过分析转基因植株的株高、分蘖数、结实率、千粒重四个主要农艺性状的变异,比较基因枪法转化的基因表达框(仅含启动子、基因开放阅读框和终止子序列)和完整质粒两种基因载体形式对水稻农艺性状的变异效应.结果表明,与非转基因亲本相比,转基因植株的千粒重和分蘖数与对照无显著差异;株高变异也不大,17个转基因株系中,仅基因表达框转化的2个株系XFb-36和XFb-63株高变矮;而结实率变异最大,有9个转基因株系结实率显著降低,变异率达50%以上.总体上看,基因表达框和完整质粒两种基因载体形式对水稻农艺性状的变异效应差异不明显,基因枪转化对水稻农艺性状的变异效应主要表现为降低植株的育性,转基因水稻植株的农艺性状变异主要来源于转基因过程中组织培养引起的无性系变异.     

转抗菌肽B基因水稻(Oryza sativa L.)植株的再生

通过研究除草剂Basta对水稻品种台安 1号愈伤组织生长的影响 ,确定了能抑制愈伤组织生长的最低剂量 ;在此基础上将抗菌肽B基因 (cecropinB)和bar基因导入了台安 1号基因组。除草剂抗性鉴定结果表明 :转基因植株表现出对Basta较强的抗性 .     

Resistance to rice blast (Pyricularia oryzae) caused by the expression of trichosanthin gene in transgenic rice plants transferred through agrobacterium method

The gene of trichosanthin has been transferred into rice plants through agrobacterium method. The single copy insertion and the expression of foreign gene have been proved in regenerated plants. In antifungal assay the degrees of rice blast (Pyricularia oryzae) infection of the transgenic plants expressing trichosanthin and expressingGUS gene as control have been evaluated. The differences such as the time of disease symptom observed, the number of infected plants and damaged leaves, the growth of infected plants of the two transgenic plants after being inoculated by rice blast (Pyricularia oryzae) are significant. The transgenic plants with trichosanthin gene grew faster than the plants withGUS gene, even when humidity environment was removed. The results show that the transgenic plants that expressed trichosanthin are able to delay the infection of rice blast compared with the plants as control. In addition, no damage caused by the expression of trichosanthin gene in transgenic plants has been observed.     

Regenerating plants from cryopreserved adventitious buds of haploids in rice

A large number of adventitious buds were induced fromin vitro cultured young inflorescences of haploids of rice. Having been subcultured on solidified subculture media at 26°C for 7 days, the adventitious buds were loaded into 1.8 mL plastic cryotubes with cryoprotectant and kept on ice for 45–60 min. After cooled at a rate of 1.0°C/min down to −40°C, the samples, were kept in liquid nitrogen. The adventitious buds which have been cryopreserved for about 30 days were thawed rapidly in 38–40°C water and then plated on solidified MS medium containing 3% sucrose, 0.5 mg/L NAA and 2.0 mg/L kinetin. After plated, 23%–32% of adventitious buds resumed growth and 15%–22% regenerated plantlets. The results of this work indicated that the adventitious buds derived fromin vitro cultured young inflorescences is a critical factor for the success and subculturing adventitious buds on MS medium containing 3% sucrose and 4% sorbitol or 20% potato extract is essential to the procedure. The effective cryoprotectant is 10% DMSO (dimethyl sulfoximide)+0.5 mol/L sorbitol. Supported by the Natural Science Foundation of Hubei Province Zhang Zhihong: born in 1963, Lecturer     

水杨醛缩乙二胺合锰(Ⅱ)对水稻幼苗生长及光合作用的影响

水杨醛缩乙二胺合锰 ( ) [Mn(salen) ]能提高水稻种子活力 ,增加叶片中的叶绿素和可溶性蛋白质含量 ,提高呼吸和净光合速率 ,促进水稻幼苗生长     

Transformation of japonica rice with RHL gene and salt tolerance of the transgenic rice plant

Overexpression of the yeast HAL2 gene increases salt tolerance of yeast and plant. Rice HAL2-like (RHL) gene was introduced into a japonica rice cultivar HJ19 with Agrobacterium tumefaciens-mediated transformation. Transgenic plants in R0 generation were selected on the principle of GUS-positive, RHL gene PCR-positive and normal growth. Hygromycin-resistant plants of some transgenic lines in R1 generation increased salt tolerance during the seedling and booting stage, being less damaged in the cytomembrane and stronger in leaf tissue viability under salt stress during booting period. Southern analysis of transgenic lines tolerant to salt in R1 generation showed that the RHL gene expression cassette had been successfully integrated into rice genome. Moreover, gene engineering breeding methodology and really salt-tolerant rice cultivar were discussed.     

反义ACC合成酶基因导入番茄的研究

 采用农杆菌介导法将携带有反义ACC合成酶基因和NPT II的表达载体pKAC导入番茄栽培品种美国大红五星102、美国大红108、美国大红王、大红II号等中.经过卡那霉素筛选后,获得了一批抗性苗,其中有3株PCR检测为阳性.实验证明,不同激素配比对番茄子叶不定芽的诱导有一定影响,适宜的农杆菌侵染时间和浓度是番茄基因转化成功与否的关键,延迟选择有利于番茄基因转化细胞的生长.     

The characteristics of CO2 assimilation of photosynthesis and chlorophyll fluorescence in transgenic PEPC rice

With PEPC, PPDK, NADP-ME and PEPC+ PPDK transgenic and untransformed rice (Orysa sativa L.), the activities of related C₄ photosynthesis enzymes, the chlorophyll fluorescence parameters, CO₂ exchange and other physiological indexes were compared, in which the physiological characteristics of PEPC transgenic rice were mainly studied. The results were as follows: (ⅰ) The activities of PEPC in PEPC transgenic rice were 20-fold higher than those in untransformed rice; the light-saturation photosynthetic rates and the carboxylation efficiency of PEPC transgenic rice were increased by 55% and 50% more than those of untransformed rice, respectively, while the CO₂ compensation point decreased by 27%. (ⅱ) The PSⅡ photochemical efficiency (F_v/F_m) and photochemical quenching (q_P) of transgenic PEPC rice decreased less in comparison with those of untransformed rice after the treatment with high light intensity (3 h) or methyl viologen (MV), a photooxidative reagent, which demonstrated that the tolerance of PEPC transgenic rice to photoinhibition and photooxidation was enhanced. (ⅲ) Under the condition of high light intensity, the activity of RuBPCase in PEPC transgenic rice did not obviously vary while the activity induced of carbonic anhydrase (CA) in PEPC transgenic rice increased by 1.8 fold. These results would provide some beneficial enlightment for revealing the mechanism of high photosynthetic efficiency and breeding with high photosynthetic efficiency in rice.     

种植转Bt水稻对固氦细菌多样性和固氮酶铁蛋白基因nifH的水平转移的影响

通过对具有不同种植年限和不同种植强度的转Bt基因水稻与非转Bt基因水稻土壤中的细菌以及固氮细菌群落结构进行研究,发现转Bt水稻的种植可能会影响土壤中微生物群落的多样性,但是这种影响的可能只是暂时的,通过对测量种植水稻的芽长实验也得出相似的结论．另外,根据16SrDNA基因构建的系统发育进化树揭示了本实验分离的固氮细菌的遗传多样性,发现实验土壤中的固氮细菌主要分为放线菌门（Actinobacteria）（92％）和α-变形菌门（α-Pro—teobacteria）两大类．分离出的8株典型的固氮菌株,其16SrDNA基因和固氮基因nifH的序列两者的分布不一致,nifH的分布更为紧凑,为固氮基因可能发生了原位水平基因转移提供了证据．     

hTR基因反义表达质粒构建及序列分析

从人的脐带血管内皮细胞中提取基因组 DNA,通过 PCR方法扩增得到了人端粒酶RNA成分 ( human telomere RNA,h TR)的基因片段 ,扩增产物经酶切克隆到逆转录病毒载体p LNCX上 ,构建了 h TR基因的反义表达质粒 .序列分析结果表明 ,PCR扩增得到的 h TR基因的 DNA序列与所发表的序列完全一致 .构建的反义表达载体中的目的基因正确地反向插入到逆转录病毒载体 p LNCX的克隆位点上 ,构成了 h TR基因的反义表达质粒     

Defense-related phenylpropanoid biosynthetic gene clusters in rice

Since colonising land,plants have undergone massive metabolic diversification.This is reflected by the numbers of metabolites that they collectively produce (es...     

Sub1A is an ethylene-response-factor-like gene that confers submergence tolerance to rice

Most Oryza sativa cultivars die within a week of complete submergence--a major constraint to rice production in south and southeast Asia that causes annual losses of over US 1 billion dollars and affects disproportionately the poorest farmers in the world. A few cultivars, such as the O. sativa ssp. indica cultivar FR13A, are highly tolerant and survive up to two weeks of complete submergence owing to a major quantitative trait locus designated Submergence 1 (Sub1) near the centromere of chromosome 9 (refs 3, 4, 5-6). Here we describe the identification of a cluster of three genes at the Sub1 locus, encoding putative ethylene response factors. Two of these genes, Sub1B and Sub1C, are invariably present in the Sub1 region of all rice accessions analysed. In contrast, the presence of Sub1A is variable. A survey identified two alleles within those indica varieties that possess this gene: a tolerance-specific allele named Sub1A-1 and an intolerance-specific allele named Sub1A-2. Overexpression of Sub1A-1 in a submergence-intolerant O. sativa ssp. japonica conferred enhanced tolerance to the plants, downregulation of Sub1C and upregulation of Alcohol dehydrogenase 1 (Adh1), indicating that Sub1A-1 is a primary determinant of submergence tolerance. The FR13A Sub1 locus was introgressed into a widely grown Asian rice cultivar using marker-assisted selection. The new variety maintains the high yield and other agronomic properties of the recurrent parent and is tolerant to submergence. Cultivation of this variety is expected to provide protection against damaging floods and increase crop security for farmers.