番茄果实成熟相关基因SlPEL和SlAPL的表达特性

分析27个代表番茄不同发育阶段和生物反应的组织特异性、含有152 635个独立EST数据库的数码表达,发现果胶裂解酶基因 (pectate lyase, SlPEL) 和番茄AP2 Like (SlAPL)的转录受果实成熟的调节。以授粉后不同发育时期的番茄(品种为美味樱桃)果实为试材, 用半定量PCR和荧光实时定量PCR分析SlPEL的表达模式,结果表明,授粉后12 d,其表达水平明显上升;授粉后16~18 d,达到第一个小高峰;28 d到最高峰;从28 d到完全成熟逐步下降到第一个小高峰的水平。SlAPL的表达模式与SlPEL类似,但其表达启动的时期迟于SlPEL。从授粉后25 d,SlAPL转录启动;授粉后28~32 d,其转录水平上升到第一个小高峰;39 d达到最高峰,以后到完全成熟略有下降。该研究也印证利用EST的数据库进行基因数码表达分析的可行性。     

Factors affecting mango (Mangifera indica L.) protoplast isolation and culture

The major factors influencing protoplast isolation and culture of mango (Mangifera indica L.) cv. Kensington Pride were investigated. The resultant protocol was used to compare plating efficiency among 4 mango cultivars. Most responses differed between proembryonic masses (PEMs) and leaf sources. Protoplast yields of 15.22 × 10⁶ g⁻¹ from PEMs and 8.68 × 10⁶ g⁻¹ from greenhouse-derived leaves were obtained in a solution of 0.7 M mannitol CPW plus 1.5% cellulase, 1% hemicellulase and 0.75% macerozyme for PEMs or 0.5 M mannitol CPW plus 1.5% cellulose, 1% hemicellulase and 1.5% macerozyme for leaves. Culture in Ca-alginate beads with initial plating densities (IPD) of 2.5 × 10⁴ Pp mL⁻¹ for PEMs and 2.5 × 10⁵ for leaves gave the highest plating efficiencies (FPE). For PEMs 1 mg L⁻¹ 2,4-d and 3.5 mg L⁻¹ kinetin gave an FPE of 2.85% whereas lower kinetin (2 mg L⁻¹) plus 0.5 mg L⁻¹ 6-BAP was most effective for leaves (FPE of 2.12%). Most protoplast mortality occurred during the first week of culture and was more severe in liquid culture. In Ca-alginate beads, protoplast survival at 14 days was higher for PEMs (30%) than leaf (21%) as was the frequency of cell division (17.6% compared to 13.6%). PEMs protoplasts continued development through embryogenesis to in vitro plantlet regeneration whereas leaf protoplasts underwent cell division up to 40-cell colonies but failed to proceed further. For PEMs, polyembryonic cvs. Kensington Pride and Keow Savoey produced higher FPE (1.95%) than monoembryonic cvs. Tommy Atkins and Keitt (1.75%). There was no effect of cultivar for leaf protoplasts.     

褐藻酸钠涂膜剂的特性研究

对褐藻酸钠凝胶经冻结和解冻处理后的持水能力、凝胶强度、弹性、韧性及状态变化等特性进行了比较试验。结果表明；褐藻酸钠凝胶的这些性质与凝胶体内的钠和钙的比率直接相关；采用２％的褐藻酸钠溶液与５％的氯化钙溶液凝胶化２ｍｉｎ，所形成的凝胶具有很好的涂膜性能。     

Response of in vitro obtained oil palm and interspecific OxG hybrids to inoculation with Phytophthora palmivora

Bud rot (BR) disease caused by Phytophthora palmivora is the most devastating disease in oil palm cultivation in America. Oil palms that survived BR epidemics were found in areas highly devastated by the disease; these palms were introduced into Cenipalma's in vitro micropropagation (cloning programme). A severity scale was developed for in vitro palms from five ortets inoculated with two different P. palmivora isolates. Then, eight ortets of Elaeis guineensis and two ortets of the OxG interspecific hybrid were evaluated in two inoculation trials under chamber growth conditions. The clone performance response was consistent with that reported in the field for the corresponding ortets, and two contrasting ortets, one susceptible (ortet 57) and one resistant (ortet 34) were identified. We monitored and compared defence responses to P. palmivora in the contrasting ortets. An increase in reactive oxygen species (ROS) production after inoculation with the pathogen was observed, with higher accumulation of H₂O₂ in the resistant plants. Catalase (CAT) activity in resistant plants increased after inoculation with the pathogen from 24 hr post‐infection (hpi) and remained high during the observation time. In the susceptible ortets, there was a significant increase on catalase activity only at 48 hpi. Peroxidase (POS) activity increased in clones from both susceptible and resistant ortets, but the increase was much greater in the susceptible ones. Phenylalanine ammonia lyase activity increased in response to inoculation, and these increases were greater in clones of the susceptible ortet than in clones of the resistant ortet.     

杨树溃疡病菌三菌系及诱导物对寄主两种酶活性的影响

测定了杨树溃疡病菌（Ｄｏｔｈｉｏｒｅｌａｇｒｅｇａｒｉａ）三菌系直接感染及三菌系代谢产物、菌丝体提取物等两类诱导物诱导毛白杨（Ｐｏｐｕｌｕｓｔｏｍｅｎｔｏｓａ）愈伤组织过氧化物酶和苯丙氨酸解氨酶的活性。结果表明,两个不同生理型的杨树溃疡病菌对寄主过氧化物酶活性的诱导作用差异较大,但对苯丙氨酸解氨酸活性诱导作用的大小与不同生理型之间没有必然联系     

中生菌素对水稻白叶枯病的防治机制

对不同白叶枯病抗性水稻品种用200μg/ml中生菌素55℃温汤药液浸种，自然降温，秧田3—4叶期和移栽前5d各用30μg/ml中生菌素处理后，于成株期剪叶接种白叶枯病菌。结果表明中生菌素前期处理，于成株期接种白叶枯病菌时，高抗、中等抗性和感病品种中过氧化物酶、苯丙氨酸解氨酶和多酚氧化酶3种酶活性都有不同程度的提高，且以中等抗性品种酶活提高最多，接种24和48h，3种酶活性较清水对照分别增加26．92％、26．74％、24．06％和7．09％、1．31％、1．60％。盆栽试验表明，中生菌素对中抗品种的防治效果最好，达58．4％。说明中生菌素对水稻防御酶活性的诱激作用是其防治白叶枯病的机制之一。     

Optimization of plant growth-promoting bacteria-assisted phytostabilization of mine tailings

Recent studies have indicated that plant growth-promoting bacteria (PGPB) can improve revegetation of arid mine tailings as measured by increased biomass production. The goals of the present study were first to evaluate how mode of application of known PGPB affects plant growth, and second to evaluate the effect of this inoculation on rhizosphere microbial community structure. PGPB application strategies investigated include preliminary surface sterilization of seeds (a common practice in phytoremediation trials) followed by a comparison of two application methods; immersion and alginate encapsulation. Results with two native desert plant species, Atriplex lentiformis and Buchloe dactyloides, suggest that seed surface sterilization prior to inoculation is not necessary to achieve beneficial effects of introduced PGPB. Both PGPB application techniques generally enhanced plant growth although results were both plant and PGPB specific. These results demonstrate that alginate encapsulation, which allows for long-term storage and easier application to seeds, is an effective way to inoculate PGPB. In addition, the influence of PGPB application on B. dactyloides rhizosphere community structure was evaluated using PCR-DGGE (denaturing gradient gel electrophoresis) analysis of bacterial DNA extracted from rhizosphere samples collected 75 d following planting. A comparative analysis of DGGE profiles was performed using canonical correspondence analysis (CCA). DGGE-CCA showed that rhizosphere community profiles from PGPB-inoculated treatments are significantly different from both uninoculated tailings rhizosphere profiles and profiles from the compost used to amend the tailings. Further, community profiles from B. dactyloides inoculated with the best performing PGPB (Arthro Mix) were significantly different from two other PGPB tested. These results suggest that introduced PGPB have the potential to influence the development of the rhizosphere community structure found in plants grown in mine tailings.     

大豆孢囊线虫果胶酸裂解酶基因Hg-pel-5的克隆与分析

【目的】克隆和分析与大豆孢囊线虫寄生密切相关的果胶酸裂解酶新基因,为研究大豆孢囊线虫寄生和致病的分子机理提供依据,并为探讨大豆孢囊线虫的防控新途径提供理论基础。【方法】通过EST分析结合RACE-PCR扩增方法,从大豆孢囊线虫中克隆出1个果胶酸裂解酶新基因;通过原位杂交和半定量PCR的方法确定基因的表达部位和分析不同发育阶段的基因表达;采用Southern杂交方法分析基因的拷贝数。【结果】 从大豆孢囊线虫中克隆出1个全长为957个碱基编码227个氨基酸残基的新果胶酸裂解酶基因Hg-pel-5（GenBank 登录号HQ123259）。Hg-pel-5 基因组由2个外显子和1个内含子组成。预测蛋白含有20个氨基酸残基的信号肽和4段细菌结构的果胶酸裂解酶第三家族的保守位点。原位杂交确定Hg-pel-5在大豆孢囊线虫亚腹食道腺中表达。半定量RT-PCR结果表明Hg-pel-5在寄生前和寄生过程早期的2龄幼虫大量表达。Southern杂交结果显示Hg-pel-5存在于大豆孢囊线虫基因组中并以多拷贝形式存在。【结论】对大豆孢囊线虫中1个新的果胶酸裂解酶基因Hg-pel-5进行克隆和分析,表明该基因在大豆孢囊线虫早期寄生过程中发挥重要作用。     

水杨酸对黄芪愈伤组织代谢产物中几种E活性的影响

目的探讨水杨酸对黄芪愈伤组织代谢产物中几种E活性的影响.方法通过添加不同浓度的水杨酸（SA）处理黄芪愈伤组织,并从提取物中检测几种酶活性的变化.结果黄芪愈伤组织代谢产物中的过氧化物酶（POD）、过氧化氢酶（CAT）、多酚氧化酶（PPO）和苯丙氨解氨酶（PAL）的活性均随水杨酸（SA）体积质量和培养时间的改变而改变,随着SA浓度的增加可提高PAL,POD及PPO的活性,但抑制CAT的活性.结论 SA体积质量在0.01 mg/L时抑制CAT活性最明显;SA体积质量在0.1 mg/L和1 mg/L时POD和PPO活性最高,并且均在36 h出现最高峰.     

基于酶技术生产低黏度及超低黏度褐藻胶的工艺

为解决当前低黏度及超低黏度褐藻胶生产工艺中存在的不足,本实验以海带为原料,利用褐藻胶裂解酶降解制备低黏度及超低黏度褐藻胶,研究了分子量、p H、温度对黏度的影响,确定了碱消化的最佳条件,探究了酶解工艺中加酶量、酶解时间及原料的初始黏度对褐藻胶产品的影响。结果显示,通过控制加酶量(100~500 U/g),酶解30 min即可得到低黏度及超低黏度褐藻胶,其中加酶量为100~330 U/g时可得到低黏度褐藻胶,加酶量增加至330~500 U/g时,可得到超低黏度褐藻胶,且酶解法得到的褐藻胶样品分子量均一度高,工艺节水率高达10%~50%;同时研究发现酶解样品黏度与原料初始黏度相关性不大,只在较短时间内表现出相关性,该工艺具有较高的原料适用性。