绿豆5个产量相关性状的QTL分析

利用绿豆(Vigna radiata)品种苏绿16-10和潍绿11杂交构建的F₂和F₃群体发掘调控绿豆产量相关性状的遗传位点。同时对绿豆产量相关性状进行表型鉴定和相关性分析, 并利用构建的遗传连锁图谱进行QTL定位。结果表明, 单株产量与单株荚数、单荚粒数、百粒重和分枝数均呈正相关。单株产量与单株荚数的相关性最高, 这2个性状在F₂和F₃群体中的相关系数分别为0.950和0.914。在F₂群体中, 共检测到8个与产量性状相关的QTL位点, 其中与单株荚数、单荚粒数和单株产量相关的QTL位点各1个, 分别解释11.09% (qNPP3)、17.93% (qNSP3)和14.18% (qYP3)的表型变异; 2个与分枝数相关的QTL位点qBMS3和qBMS11, 分别解释18.51%和7.06%的表型变异; 3个与百粒重相关的QTL位点qHSW3、qHSW7和qHSW10, 分别解释5.33%、46.07%和4.24%的表型变异。在F₃群体中, qNSP3和qHSW7再次被检测到, 表明这2个QTLs有较好的遗传稳定性。同时, 开发了1个与百粒重主效QTL qHSW7紧密连锁的InDel标记R7-13.4, 并利用自然群体对该分子标记辅助筛选的有效性进行了验证。研究结果可为绿豆产量相关性状基因的定位、克隆及分子标记辅助育种提供参考。     

Contrasting photo- and thermoperiod-induced changes in abscisic acid and lipid contents in leaves of mungbean seedlings

Seedlings of Phaseolus aureus ROXB were grown under 12/12 h light/dark cycles with the light period at 32.5°C and darkness at 10°C (normal conditions N) or with light at 10°C and darkness at 32.5°C (inverse conditions, I). I-conditions affected the level of chlorophyll and carotenoids (very low), monogalactosyldiacylgycerol (low) and phosphatidylinositol (high) in the leaves. Leaves of I-seedlings showed a sharp and durable decline of relative water content during the low temperature phase. For the N-seedlings, loss of water was restricted to the end of this period. The loss of water was accompanied by visible symptoms of wilting at specific times of day. Although the pigment content remained nearly unchanged, ABA content of leaves of both N-and I-seedlings increased during water stress. Upon return to the warm period, ABA level continued to increase after the leaves had regained turgor, this 'after stress'increase being more pronounced in the leaves of I-seedlings. Exogenous application of ABA induced a slight increase in the content of phospholipids in N- and I-leaves and a decrease in free fatty acids, whereas monogalactosyldiacylglycerol content was significantly reduced in N-leaves after application of ABA. Upon transfer of I-plants to 20°C for 12 h during the light period, pigment and chloroplastic lipid content increased rapidly whereas upon a further exposure to 10°C in light, pigments and especially monogalactosyldiacylglycerol were lost. The control of pigment and lipid metabolism and the role of ABA during chilling stress are discussed.     

New microsatellite markers isolated from mungbean (Vigna radiata (L.) Wilczek)

In this study, we reported the isolation and analysis of new polymorphic microsatellites in mungbean (Vigna radiata (L.) Wilczek). Twelve out of 210 primer pairs screened in 30 mungbean accessions gave polymorphism. The polymorphic markers detected two to three alleles per locus with an average of 2.08. Observed heterozygosity varied from 0 to 0.133, while expected heterozygosity ranged from 0.095 to 0.498. Tests for Hardy-Weinberg equilibrium (HWE) and pairwise linkage disequilibrium of the polymorphic loci revealed that all loci except MB-SSR14 significantly departed from HWE and four pairwise combinations, viz. MB-SSR14 vs. MB-SSR42, MB-SSR42 vs. MB-SSR87, MB-SSR114 vs. MB-SSR121, and MB-SSR175 vs. MB-SSR231 significantly deviated from linkage disequilibrium. The markers are being used to study genetic diversity and genome mapping of mungbean.     

表油菜素内酯对黄化绿豆下胚轴切段MACC、ACC和乙烯生成的影响

1979年Grove等从油菜花粉分离得到一种新的植物生长调节物质——油菜素内酯,它具有生长素、赤霉素类似活性,并与生长素有加合作用(Yopp等 1979,1981;Takeno和Pharis 1982)。诱导乙烯产生是生长素一个显著的生物效应;Yopp等(1979)和Arteca等(1983)分别报道过油菜素内脂对绿豆等生长素诱导乙烯增加的加合作用,促进乙烯前体1-氨基环丙烷基-1-羧酸的合成(Schlagnhaufer等1984)。本文主要研究了BR及其与IAA共同对ACC和乙烯生成的影响的特征及其对MACC形成的促进作用。     

Estimation of Genetic Variability of Vigna radiata Cultivars by RAPD Analysis

DNA was isolated from 14 cultivars of Vigna radiata (L.) Wilczek and subjected to RAPD analysis using 14 random decamer primers. These cultivars revealed polymorphism with respect to RAPD markers and were subjected to hierarchical cluster analysis. A dendrogram was prepared based on these data. Analysis of banding patterns confirmed that two strongly aromatic cultivars IC1, IC4, were closely linked. But another aromatic cultivar, B1, formed a separate cluster. The high yielding cultivars were closely related to B1. The phylogenetic tree constructed by the neighbour joining method showed that RAPD results were correlated with morphological characters like plant height, leaf and seed size, seed colour, etc. This revised version was published online in July 2006 with corrections to the Cover Date.     

渗透胁迫对绿豆叶圆片叶绿素荧光的影响

绿豆叶圆片用0、-0．3、-0．6、-1．2、-1．8、-2．4MPa等6个渗透梯度处理24h后,其叶绿素荧光的反应表明：光系统Ⅱ的潜在量子产量(FD／Fm)和电子传递受体(QA)的库容(pool size)均随胁迫强度的增大而减小,但QA库容的下降明显比Fg／Fm的下降缓和。结合原初荧光Fo和最大荧光Fm的变化,分析认为本实验中渗透胁迫并未导致明显的光系统Ⅱ反应中心的失活或破坏。造成光系统Ⅱ潜在量子效率降低的原因主要是通过光系统Ⅱ反应中心到Ⅱ的电子传递受到阻抑。     

Inter organ comparison of amylases and starch content in mungbean seedlings

During seedling growth of mungbean in dark, depletion of cotyledonary starch is reflected by an increase in starch content of root and shoot. With progress of seedling growth, amylolytic activity increases in all organs i.e. cotyledons, shoots and roots. A rapid turnover of starch in shoots and roots has been proposed. Amylase activity of seedlings was in the order of cotyledons>shoots>roots. Five days after germination (DAG) α-amylase from cotyledons of mungbean seedlings was purified using ammonium sulphate precipitation, DEAE cellulose and sephadex G-150 column chromatography. Phytic acid was a stronger inhibitor of α-amylase than EDTA. Phytic acid, Hg²⁺, Zn²⁺ and Mn²⁺ were non-competitive inhibitors and the corresponding Ki values were 5.0–5.7, 0.36–0.38, 2.6–3.8 and 0.7–0.8 mol·M⁻³. Elution patterns of α-amylases of cotyledons, shoots and roots on sephadex G-100 column showed that cotyledonary α-amylase had a higher molecular mass than that of shoot and root α-amylases which had identical molecular masses. All α-amylases showed the same optimum pH 5.0 whereas optimum temperature was 55 °C for cotyledonary and 45 °C for shoot and root α-amylases. In all these tissues α-amylases were stable to 30 min heat treatment at 50 °C however unlike cereal α-amylases they lost activity at 70 °C. Km for α-amylases from cotyledons, shoots and roots with starch was 1.9, 4.3 and 6.6 mg per cm³, respectively. α-amylase of cotyledons and roots showed activity in reactions with various substrates in the order of starch>amylose>dextrin-I=dextrin-IV>α-cyclodextrin=β-cyclodextrin>amylopectin>pullulan. The shoot α-amylase showed high activity with amylopectin, which was comparable with that obtained with amylose, and the activity with α and β-cyclodextrin was higher in comparison with dextrin-I and IV. The α-amylases from these tissues liberated maltose, maltotriose and higher oligosaccharides from starch. It could be concluded that amylases from different organs of a seedling could have different physical and kinetic properties.     

Genomics and molecular breeding in lesser explored pulse crops: Current trends and future opportunities

Pulses are multipurpose crops for providing income, employment and food security in the underprivileged regions, notably the FAO-defined low-income food-deficit countries. Owing to their intrinsic ability to endure environmental adversities and the least input/management requirements, these crops remain central to subsistence farming. Given their pivotal role in rain-fed agriculture, substantial research has been invested to boost the productivity of these pulse crops. To this end, genomic tools and technologies have appeared as the compelling supplement to the conventional breeding. However, the progress in minor pulse crops including dry beans (Vigna spp.), lupins, lablab, lathyrus and vetches has remained unsatisfactory, hence these crops are often labeled as low profile or lesser researched. Nevertheless, recent scientific and technological breakthroughs particularly the next generation sequencing (NGS) are radically transforming the scenario of genomics and molecular breeding in these minor crops. NGS techniques have allowed de novo assembly of whole genomes in these orphan crops. Moreover, the availability of a reference genome sequence would promote re-sequencing of diverse genotypes to unlock allelic diversity at a genome-wide scale. In parallel, NGS has offered high-resolution genetic maps or more precisely, a robust genetic framework to implement whole-genome strategies for crop improvement. As has already been demonstrated in lupin, sequencing-based genotyping of the representative sample provided access to a number of functionally-relevant markers that could be deployed straight away in crop breeding programs. This article attempts to outline the recent progress made in genomics of these lesser explored pulse crops, and examines the prospects of genomics assisted integrated breeding to enhance and stabilize crop yields.     

Isolation of microsatellite markers in mungbean,Vigna radiata

A simple and rapid method for isolating microsatellite loci in mungbean, Vigna radiata, based on the 5′‐anchored polymerase chain reaction technique revealed 23 microsatellite loci and six cryptically simple sequence repeats. We report on the characterization of seven polymorphic microsatellite loci in V. radiata. The number of alleles per locus ranged from 2 to 5 while the observed heterozygosity ranged from 0 to 0.9048. These markers should prove useful as tools for detecting genetic variation in mungbean varieties for germplasm management and crossbreeding purposes.