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Feng B.-H.,Sun Yat Sen University | Feng B.-H.,Guangxi University | Wu B.,Sun Yat Sen University | Wu B.,Guangzhou Academy of Agricultural science | And 5 more authors.
Journal of Plant Physiology | Year: 2012

Embryogenic callus (EC) induced from petioles of alfalfa (Medicago sativa L. cv. Jinnan) on B5h medium turned green, compact and non-embryogenic when the kinetin (KN) in the medium was replaced partially or completely by thidiazuron (TDZ). The application of CoCl 2, which is an inhibitor of 1-aminocyclopropane-1-carboxylate oxidase (ACO), counteracted the effect of TDZ. Ethylene has been shown to be involved in the modulation of TDZ-induced morphogenesis responses. However, very little is known about the genes involved in ethylene formation during somatic embryogenesis (SE). To investigate whether ethylene mediated by ACO is involved in the effect of TDZ on inhibition of embryogenic competence of the alfalfa callus. In this study we cloned full-length ACO cDNA from the alfalfa callus, named MsACO, and observed changes in this gene expression during callus formation and induction of SE under treatment with TDZ or TDZ plus CoCl 2. RNA blot analysis showed that during the EC subcultural period, the expression level of MsACO in EC was significantly increased on the 2nd day, rose to the highest level on the 8th day and remained at this high level until the 21st day. However, the ACO expression in the TDZ (0.93μM)-treated callus was higher than in the EC especially on the 8th day. Moreover the ACO expression level increased with increasing TDZ concentration during the subcultural/maintenance period of the callus. It is worth noting that comparing the treatment with TDZ alone, the treatment with 0.93μM TDZ plus 50μM CoCl 2 reduced both of the ACO gene expressions and ACO activity in the treated callus. These results indicate that the effect of TDZ could be counteracted by CoCl 2 either on the ACO gene expression level or ACO activity. Thus, a TDZ inhibitory effect on embryogenic competence of alfalfa callus could be mediated by ACO gene expression. © 2011. Source


Guo S.,China Agricultural University | Guo S.,Guangzhou Academy of Agricultural science | Ma N.,China Agricultural University | Yang W.-C.,China Agricultural University | And 2 more authors.
Agricultural Sciences in China | Year: 2011

Fertility restoration of cytoplasmic male-sterility in pepper (Capsicum annuum L.) is useful for commercial production of hybrid seeds. However, the mechanism of fertility restoration has not been determined. We previously constructed a cDNA library and identified some genes related to fertility restoration in pepper using suppression subtractive hybridization technology. In this study, the expression patterns of 20 genes were investigated using semi-quantitative RT-PCR. Three genes expressed only in restorer lines, but not in sterility lines. Four genes expressed only in anther, but not in other organs. Among these 7 genes, the clone TG31 was observed to specifically express in anther of restorer lines. The work described here provides a comprehensive overview on the expression pattern of the genes that are induced by restorer alleles in pepper. It will also contribute to the current understanding of molecular networks for the regulation of fertility restoration. © 2011 Chinese Academy of Agricultural Sciences. Source


Liang Q.,South China Agricultural University | Cheng X.,China Agricultural University | Cheng X.,Guangzhou Academy of Agricultural science | Mei M.,China Agricultural University | And 2 more authors.
Annals of Botany | Year: 2010

Background and Aims: Low phosphorus (P) availability is a major constraint to soybean growth and production, especially in tropical and subtropical areas. Root traits have been shown to play critical roles in P efficiency in crops. Identification of the quantitative trait loci (QTLs) conferring superior root systems could significantly enhance genetic improvement in soybean P efficiency. Methods: A population of 106 F9 recombinant inbred lines (RILs) derived from a cross between BD2 and BX10, which contrast in both P efficiency and root architecture, was used for mapping and QTL analysis. Twelve traits were examined in acid soils. A linkage map was constructed using 296 simple sequence repeat (SSR) markers with the Kosambi function, and the QTLs associated with these traits were detected by composite interval mapping and multiple-QTL mapping. Key Results: The first soybean genetic map based on field data from parental genotypes contrasting both in P efficiency and root architecture was constructed. Thirty-one putative QTLs were detected on five linkage groups, with corresponding contribution ratios of 9 1-31 1 %. Thirteen putative QTLs were found for root traits, five for P content, five for biomass and five for yield traits. Three clusters of QTLs associated with the traits for root and P efficiency at low P were located on the B1 linkage group close to SSR markers Satt519 and Satt519-Sat-128, and on the D2 group close to Satt458; and one cluster was on the B1 linkage group close to Satt519 at high P. Conclusions: Most root traits in soybean were conditioned by more than two minor QTLs. The region closer to Satt519 on the B1 linkage group might have great potential for future genetic improvement for soybean P efficiency through root selection. © The Author 2010. Source


Tian Y.,South China Agricultural University | Tian Y.,Guangzhou Academy of Agricultural science | Liang G.,South China Agricultural University | Zeng L.,South China Agricultural University | Cao L.,South China Agricultural University
Shengtai Xuebao/ Acta Ecologica Sinica | Year: 2012

Different plant habitats provide different shelters and prey or host for natural enemies, thereby influencing the maintenance and propagation of the population of enemies. Therefore, which kind of crops to plant in the field is vital to the conservation of natural enemies. Presently, there have been lots of studies concerning the effect of crop diversity on community structure and population dynamics of arthropods, but the chill conservation effect of post-crop habitats on the natural enemies has rarely been reported. Sweet corn, a neonatal variety, has been planted on a large scale in south China. To make full use of biological control on the insect pests of sweet corn, it's necessary to study the conservation effect of natural enemies in different post-crop habitats. In this paper, investigation was conducted to study the community structure and the time dynamics of natural enemy in maize field with different plant habitats (corn-stalk, leafy vegetable, sweet potato or weed) after autumn corn harvest by means of netting method and visual observation. The different chill conversation effects on natural enemies among different habitats were also discussed with cluster analysis. Results showed that the corn-stalk was listed as the habitat with the largest number of natural enemies, i.e. as many as 555, which was about twice of the leafy vegetable habitats (Brassica oleracea, Brassica campestris or Lactuca sativa), and 4.5 times of weed habitat or sweet potato habitat. Spiders, which took up eighty percent of the total natural enemies in B.oleracea, sweet potato or weed habitat, were the main group of natural enemies. Nevertheless, the dominant species of natural enemies in corn stalks habitat was Micraspis discolor (Fabricius), with more than 30 individuals per hundred plants. The magnitude of number of natural enemy species or diversity index was as "corn stalks habitat>leafy vegetables habitats≥ weed habitat> sweet potato habitat", while dominant concentration index of natural enemy community was to the contrary. Results also indicated that all the six plant habitats could be classified into 3 groups, i.e. the corn stalk habitat group, the leafy vegetable habitat group and the weed and sweet potato habitat group. Both the total number and the species of natural enemies were the mostplentiful in the corn stalk habitat. In the leafy vegetable habitat, dynamics of the characteristic of community structure of natural enemies was steady, with a great number of enemy individuals but less species. On the contrary, neither enemy individuals nor species number was abundant in the weed and sweet potato habitat. In conclusion, the corn stalk habitat had the best chill conservation effect on natural enemies in maize field. In south China, the leafy vegetables are often planted after autumn corn harvest. Researches suggested that during the period of vegetable production at winter, the corn stalk should be reserved between crop rows in order to protect the natural enemies to the most. Source


Cui J.,South China Agricultural University | Cheng J.,South China Agricultural University | Wang G.,South China Agricultural University | Tang X.,South China Agricultural University | And 4 more authors.
Euphytica | Year: 2014

To identify quantitative trait loci (QTLs) for flower-related characters in Luffa, a genetic map was constructed by using 110 F2 individuals derived from interspecific hybrids between Luffa acutangula Roxb. (inbred line ‘28-0-0’) and L. cylindrica Roem. (inbred line ‘37-0-1-1’). A total of 258 sequence-related amplified polymorphism markers were mapped on 24 linkage groups, spanning 822.86 cM, with a mean marker interval of 3.49 cM. Then, 23 QTLs were identified through composite interval mapping, and included nine, eight and six for first female flower node, male flower diameter and flowering time, respectively. Importantly, the above QTLs individually explained 0.03–24.61 % of total phenotypic variance of the corresponding trait. These findings provide a basis for molecular marker assisted breeding in Luffa. © 2014, Springer Science+Business Media Dordrecht. Source

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