花青素积累相关负调控因子的研究进展

植物花青素的积累受正调控因子与负调控因子的影响,过去多集中于对正调控因子的研究,而最近注意到负调控因子对于保证植物正确响应发育及环境信号,进而精细调控花青素的积累具有重要作用。从结构特征,作用机制,参与的调控途径等方面综述了与植物花青素积累相关的负调控因子的研究进展,根据其对花青素合成关键基因的调控方式分为转录水平调控的转录抑制因子、参与转录后水平调控的负调控因子以及具体作用机制尚不明确的因子3 大类,并对相关后续研究方向进行了探讨。     

花色素苷生物合成与分子调控研究进展

花色素苷是决定植物花色的主要色素,其生物合成是目前研究得最为清楚的植物次生代谢途径之一。花色素苷的生物合成主要由于F3H,F3'H和F3'5'H三个关键酶的作用形成3个分支,最终分别生成橙色到砖红色的天竺葵素糖苷,红色的矢车菊素糖苷和蓝色到紫色的飞燕草素糖苷,因此, F3'H,F3'5'H和DFR基因是利用遗传转化引入花卉植物原本缺乏的花色代谢途径的关键基因。花色素苷合成结构基因的转录调控是目前研究的热点,对结构基因的转录进行调控的转录因子主要包括两大类相互作用的因子－bHLH和MYB类转录因子,花色素苷合成的转录调控机理的基本模式,包括bHLH和MYB类因子之间的相互作用,以及它们对结构基因顺式元件的识别和结合已经阐述的比较清楚。另外,对于一些处于bHLH和MYB上游的, WD40类因子和光敏色素的研究开启了从信号传导到花色素苷合成的整个调控过程的研究。     

园艺植物中类胡萝卜素合成与调控的研究进展

园艺植物富含类胡萝卜素,提高类胡萝卜素含量是园艺作物育种目标之一。概述了近年来在高等植物中类胡萝卜素的合成、氧化裂解和其它衍生代谢途径的研究进展,并在结构基因调控、转录因子调控、转录后调控和库源调控等多个层面上阐述了类胡萝卜素生物合成调控机制。其中,调控类胡萝卜素合成的转录因子已经成为近年来研究的热点,主要分为直接调控类胡萝卜素合成和影响果实成熟进而间接调控类胡萝卜素合成两大类。随着研究的不断深入,新转录因子、新基因和新调控方式正不断被挖掘。     

中国农大揭示植物在黑暗下的ABA信号转导机制

中国农业大学生物学院植物生理学与生物化学国家重点实验室李继刚课题组揭示了转录因子PHYTOCHROME-INTERACTING FACTORS(PIFs)通过直接结合ABI5基因的启动子并且激活ABI5的表达,在黑暗下特异调控植物的ABA信号途径;该研究还发现ABA受体PYL8/PYL9能够和PIFs直接相互作用,并且介导PIFs对ABI5的转录调控;此外,该研究进一步支持了某些ABA受体通过与转录因子互作,直接调控基因表达的工作模式;综上,研究证明了植物中存在黑暗下特异的ABA信号调控组分和途径,有助于进一步理解植物如何根据环境的光信号调整其内源的ABA信号途径,从而在自然界获得更好的生存能力,还为PIFs这类重要转录因子在植物中参与的信号途径及调控机制提供了新的见解。     

钙对果树生理特征影响的研究进展

钙在促进果树正常生长发育以及抗逆生理上发挥着重要作用。研究发现,钙参与果树体内组织结构的形成、营养与生殖器官的发育、光合作用等植物生理过程以及保护酶系统和免疫系统的调控等植物生理生化发育进程。本文对钙在果树生长发育中的生理功能、钙对果树叶片及果实生理的影响、钙对调控果树免疫及抑制果树病害的作用三方面的国内外研究进展进行总结性阐述,并对今后的研究进行了展望,以期为钙在果树上的进一步研究及应用提供一定的理论基础。     

植物萜类合成酶及其代谢调控的研究进展

 萜类是植物中一类重要的次生代谢物,具有重要的生理生态作用及经济价值。萜类合成酶是萜类化合物形成的关键酶,包括单萜合成酶、倍半萜合成酶和二萜合成酶等,其种类和功能决定了萜类的多样性。萜类合成代谢具有明显的组织特异性,并受植物发育进程的调控,外界生物与非生物因子对其代谢有显著影响。基因工程技术在一定程度上改变了转基因植株中萜类的组分和含量。综述了近年来在萜类合成酶结构、分类和作用机理以及萜类代谢调控的研究进展。     

梨芽内休眠分子调控机制研究进展

多年生木本植物芽休眠是植物生长发育过程中的一种可见生长暂时停止的现象,是植物经过长期演化而获得的一种对环境及季节性变化的生物学适应性。对梨芽内休眠分子机制研究的最新进展进行了综述,阐述了梨休眠的建立与解除过程的调控因素,介绍了梨内休眠过程重要转录因子DAM的发现及其参与的分子网络调控模式,并对有关休眠机制未来的研究方向提出了展望。     

果树miRNAs研究进展

模式植物的研究表明,miRNA作为一种转录后调控因子,在植物的生长发育、逆境胁迫应答等生物学过程中发挥着重要的调节作用。截至目前,虽然已经从多种果树中鉴定了大量的miRNAs,但大多数miRNAs的靶基因和功能特性还不清楚。笔者总结了目前果树中miRNAs的研究进展,特别是miRNAs在葡萄(Vitis vinifera)、桃(Prunus per-sica)、梨(Pyrus spp.)、苹果(Malus domestica)和柑橘(Citrus spp.)等具有重要经济价值的果树等方面的作用,比如调控果树生长发育与果实品质、激素信号转导和环境胁迫应答。探讨了果树miRNAs的前景和研究方向。     

番茄果实中类胡萝卜素合成与调控的研究进展

番茄是果实成熟研究中的模式植物，在番茄果实成熟过程中，类胡萝卜素种类与含量变化是影响果实着色和品质的重要因子，其相关研究也备受关注。本文综述了近年来国内外学者在番茄果实类胡萝卜素合成与调控等方面的研究进展，阐述了番茄果实中类胡萝卜素的种类、分布与含量，番茄果实在发育过程中类胡萝卜素的含量变化规律，以及参与类胡萝卜素合成的关键酶和转录因子等的研究进展，并对未来该热点问题的发展方向进行了展望。     

植物MYB转录因子调控苯丙烷类生物合成研究

植物苯丙烷类化合物和人类生活密切相关,可用于生产医药、染料、农药、香料等。但是其生物合成也是非常复杂的过程,严格受到植物细胞内基因表达时间和空间的调控。该研究总结了植物苯丙烷类物质的生物合成途径及参与植物苯丙烷类物质合成调控的转录因子,重点阐述了MYB转录因子调控木质素的生物合成过程、R2R3 MYB转录因子调控黄酮醇及花青素的生物合成过程,并提出了植物苯丙烷类物质代谢研究存在的问题,以期为苯丙烷类化合物的研究和利用提供理论参考。     

Induction of resistance in Yali pear (Pyrus bretschneideri Rehd.) fruit against postharvest diseases by acibenzolar-S-methyl sprays on trees during fruit growth

The objective of this work was to evaluate how disease resistance in harvested fruit of Yali pears (Pyrus bretschneideri Rehd.) may be affected by acibenzolar-S-methyl (ASM) sprays on trees. Results showed that disease incidence and lesion diameter in mature pears from trees sprayed with ASM for three times during growth and inoculated with Penicillium expansum or Alternaria alternata after harvest were 27.9 and 42.7%, or 29.1 and 23.4% lower, respectively, than in control fruit 17 days after inoculation. Mature fruit from ASM-treated trees exhibited higher activities of defense enzymes including phenylalanine ammonia-lyase (PAL), chitinase and β-1,3-glucanase than in control at harvest. In young pears, activities of peroxidase, polyphenoloxidase, PAL, chitinase and β-1,3-glucanase were significantly enhanced by ASM after first spray on trees. The ASM spray also significantly increased H₂O₂ level and glutathione reductase activity, but reduced activities of catalase and ascorbate peroxidase in young pears. The study indicated that enhancement of disease resistance in harvested Yali pear fruit could be the result of multiple effects of several factors related to plant defenses induced by ASM sprays on trees during fruit growth. Application of ASM in the field holds great promise for controlling postharvest diseases of the fruit.     

果树根构型及其与营养和激素的关系

不仅树型(株型)影响果树产量和质量,根构型对果树生产也有重要意义。介绍了根构型的特点、根构型对环境营养状况的反应及其对养分吸收的影响,以及营养因素和激素对根构型的影响。指出果树根构型比1年生作物更加多样化,骨干根与毛细根的发生和生长状况是影响根构型的主要因素,果树可以通过根系变长、变细以及数量和密度的增加等方式改变根构型;生长素、细胞分裂素、乙烯和赤霉素等植物激素对根构型构建起主要调节作用,营养元素可以通过内源激素调控果树的根构型。根构型与养分吸收有很大的关联,通过构型的改变,可以增加根系与介质的接触表面积,促进营养元素的吸收利用。加强果树根构型研究,揭示果树根构型与营养的关系,构建理想根构型,对于果树根系管理和养分的高效利用有重要价值。     

壳寡糖在早熟梨生产中的应用研究

壳寡糖(chito-oligosaccharide,COS)是一种植物诱抗剂,在植物生长调节及诱导植物抗逆性和抗病性等方面显示了极大的应用潜力。试验研究发现,在早熟梨生产中喷施壳寡糖50mg.L-1,可明显增强树势,提高抗病能力,促进生长,减少落果,防止梨树早期落叶,单株产量提高18.5%以上,梨果可溶性固形物含量增加0.8个百分点以上,对提高产量和改善品质效果显著。     

White light prevents increased catechin synthesis by ultraviolet irradiation in banana fruits

Irradiation of green banana fruit (Musa AAA, Cavendish subgroup, ‘Williams’) with an ultraviolet (UV)-C fluence of 720 Jm'2 increased ethylene evolution five-fold compared with controls during the first 24 h in either dark or light. The activity of phenylalanine ammonia-lyase (PAL) in extracts from the outer peel of irradiated fruit increased at least two-fold in either light or dark, but at 20°C it took 1-2 d for PAL activity to increase above the rate in controls. Irradiation did not affect the content of total phenolic compounds in outer peel in either dark or light until 4-6 d later. The content of chlorogenic acid was also not increased in either dark or light by UV-C. The catechin content of outer peel doubled in the dark within 24 h of irradiation and continued to increase six-fold during the first three days after irradiation. Exposure to white light (13.2 Wm 2) after irradiation almost completely prevented this increase in catechin content. These results show a close metabolic relationship between catechin and the bronze pigment previously reported in bananas irradiated with UV-C.     

番茄心室胶状物的发育及其调控机制

番茄心室胶状物的形成是肉质浆果发育的重要过程和典型特征,在调控果实成熟、风味与质地变化以及种子的发育和休眠等过程中具有重要作用。果实发育过程中,胎座外层组织分化形成心室组织,最终形成高度液泡化的胶状物。这一过程中所涉及的细胞分化、分裂与膨大等是植物发育生物学研究的重要问题。植物激素、水解酶、细胞周期与转录因子等对心室胶状物的形成具有重要作用,其中AGAMOUS基因家族与核内复制可能是调控心室胶状物形成的关键因子。对番茄心室胶状物的发育、形成及其调控因子的相关研究进行了综述,为进一步揭示胶状物的形成和调控机制提供参考。     

外置式秸秆反应堆对日光温室番茄生长发育的影响

以番茄"魁冠108"为试材,研究了外置式秸秆反应堆在越冬茬栽培过程中对晴天温室内CO2含量和番茄植株营养生长及叶片叶绿素含量以及番茄坐果数、果实产量和品质的影响。结果表明:外置式秸秆反应堆能有效缓解日光温室内CO2亏缺现象;使营养生长期和结果期番茄植株净光合速率分别提高了19.5%和27.8%;显著提高番茄植株在营养生长期和结果期叶片叶绿素含量,促进番茄植株的生长;单果重增加32.59g,产量增加1 303.8kg/hm2。     

果树砧穗互作研究进展

果树砧穗互作相关机理的研究对于揭示嫁接亲和性、营养平衡以及信号调控器官形态建成具有重要意义。综述了果树砧穗互作相关机制,并指出目前存在问题和未来发展方向。研究表明:(1)砧穗间细胞正确识别和信息交流是嫁接正常愈合的关键,生理生化代谢物质也影响嫁接体的愈合;(2)嫁接体成活后,砧木直接影响接穗营养水平,接穗调控砧木根系生长发育并产生反馈作用,砧穗间内源激素含量及比例和一些可远距离传递的信号物质参与调控嫁接体发育过程;(3)嫁接杂交为果树育种提供新的方向。未来应进一步研究内源激素如何调控嫁接愈合及嫁接体营养运输、远距离移动的信号物质和嫁接遗传物质改变的分子机制。     

Effect of plant growth promoting rhizobacteria on young apple tree growth and fruit yield under orchard conditions

The effects of rootstocks (M9 and MM 106), cultivars (Granny Smith and Stark Spur Golden) and growth promoting rhizobacteria (OSU-142, OSU-7, BA-8 and M-3) on the tree growth and yield at apple (Malus domestica Borkh) trees were studied in a clay loam soil in the eastern Anatolia region of Turkey in 2002–2004. Plant growth promoting rhizobacteria (PGPR) were capable of producing indole acetic acid (IAA) and cytokinin, but three of them (OSU-7, BA-8 and M-3) were also able to dissolve phosphate. Maximum shoot number of apple trees was found after inoculation with BA-8 followed by OSU-7 and M-3. All the inoculated PGPR strains contributed to the increase in fruit yield of apple when compared to control but it was strongly depended on rootstocks, cultivars and treatments. Plant growth responses were variable and dependent on bacterial strains, rootstock and cultivar and growth parameters evaluated of young apple trees. Newly planted apple trees inoculated with OSU-142, OSU-7, BA-8 and M-3 PGPR increased average shoot length by 59.2, 18.3, 7.0 and 14.3% relative to the control and fruit yield by 116.4, 88.2, 137.5 and 73.7%, respectively. Bacterial inoculation increased shoot diameter from 7.0 to 16.3% when compared to control. The production of plant growth hormones has been suggested as one of the mechanisms by which PGPRs stimulate young apple sapling growth. The growth-promoting effect appears to be direct, with possible involvement of the plant growth regulators indole-3-acetic acid and cytokinin. In view of environmental pollution due to excessive use of fertilizers and high costs of the production of fertilizers, PGPR strains tested in our study have potential to be used for the sustainable and environmentally benign horticultural production.     

Control of black spot disease caused by Alternaria alternata on jujube (Ziziphus jujuba Mill. cv. Dongzao) using HarpinXoo protein

Summary

Currently, no adequate control measures exist for the fungal disease, black spot (Alternaria alternata (Fr.) Keissler) on ‘Dongzao’ jujube (Ziziphus jujuba Mill. cv. Dongzao). Black spot is an important factor limiting jujube fruit yield under certain conditions. In this study, three concentrations (10, 20, or 30 µg ml^–1) of the Harpin_Xoo protein, or water (negative control), were sprayed onto ‘Dongzao’ jujube trees to control black spot disease. Following Harpin_Xoo protein treatment, its effects on the control of black spot disease were determined, and the levels of a defence-related substance [i.e., salicylic acid (SA)], and the activities of peroxidase (POD), polyphenol oxidase (PPO), and phenylalanine ammonia lyase (PAL) were measured. The incidence of black spot disease was significantly decreased, compared with water-treated control, fruit by ≤ 88.4%. After 2 d, SA levels, and POD, PPO, and PAL activities in Harpin_Xoo-treated fruit were clearly higher than those in control fruit. After fruit had been stored for 45 d at 0ºC, SA levels, and POD and PPO activities showed no differences between the Harpin_Xoo treatments and the controls, but PAL activities in Harpin_Xoo-treated fruit were lower than those in the controls. The most appropriate concentration of Harpin_Xoo protein to control black spot disease was 20 µg a.i. ml^–1. These results suggest that the Harpin_Xoo protein induced systemic acquired resistance in ‘Dongzao’ jujube trees and may offer a worthwhile strategy for disease control.     

激发子物质处理富士苹果果实后抗轮纹病病菌侵染的研究

富士苹果果实经硝普钠(SNP)、茉莉酸甲酯(MeJA)、水杨酸(SA)和氯化钙处理后再接种轮纹病菌,各个处理均能不同程度地防止轮纹病菌的侵染和扩展,其中MeJA和SNP处理效果最明显,烂果率和烂果面积分别比对照减少26.7%、26.7%和41.6%、36.2%。另外,还对各处理果实的PAL、SOD、POD和PPO活性变化进行了分析,结果表明,接种轮纹病菌的72h内,4个处理的PAL和PPO活性均表现出先升后降的趋势,而SOD和POD活性变化除SA处理一直保持平稳波动上升外,其余3个处理也表现为先升后降趋势;各处理的PAL和POD峰值出现的时间均早于SOD和PPO。PAL、POD和PPO活性峰值和平均值均以MeJA处理最高,SOD活性峰值和平均值SNP处理最高。