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Li X.,Huazhong Agricultural University | Chen L.,Guizhou Academy of Agricultural science | Hong M.,Huazhong Agricultural University | Zhang Y.,Guangdong Academy of Agriculture science | And 7 more authors.
PLoS ONE | Year: 2012

Yellow seed is a desirable quality trait of the Brassica oilseed species. Previously, several seed coat color genes have been mapped in the Brassica species, but the molecular mechanism is still unknown. In the present investigation, map-based cloning method was used to identify a seed coat color gene, located on A9 in B. rapa. Blast analysis with the Arabidopsis genome showed that there were 22 Arabidopsis genes in this region including at4g09820 to at4g10620. Functional complementation test exhibited a phenotype reversion in the Arabidopsis thaliana tt8-1 mutant and yellow-seeded plant. These results suggested that the candidate gene was a homolog of TRANSPARENT TESTA8 (TT8) locus. BrTT8 regulated the accumulation of proanthocyanidins (PAs) in the seed coat. Sequence analysis of two alleles revealed a large insertion of a new class of transposable elements, Helitron in yellow sarson. In addition, no mRNA expression of BrTT8 was detected in the yellow-seeded line. It indicated that the natural transposon might have caused the loss in function of BrTT8. BrTT8 encodes a basic/helix-loop-helix (bHLH) protein that shares a high degree of similarity with other bHLH proteins in the Brassica. Further expression analysis also revealed that BrTT8 was involved in controlling the late biosynthetic genes (LBGs) of the flavonoid pathway. Our present findings provided with further studies could assist in understanding the molecular mechanism involved in seed coat color formation in Brassica species, which is an important oil yielding quality trait. © 2012 Li et al.

Guo D.,South China Normal University | Guo D.,Guangdong Academy of Agriculture science | Liang J.,South China Normal University | Qiao Y.,Guangzhou Academy of Agriculture Science | And 3 more authors.
Journal of Plant Physiology | Year: 2012

Previous study indicated that increasing endogenous abscisic acid (ABA) level could inhibit the lateral root (LR) formation of peanuts. In this study, we investigated the mechanisms by which ABA regulated lateral root primordia (LRP) initiation in peanuts (Arachis hypogaea L). Results suggested that ABA inhibited LRP initiation through blocking G1-to-S transition in seedlings and mature roots: e.g. 5.8% increase in the proportion of G1 phase and 18% decrease in the proportion of S phase after ABA treatment for 6 days. Further study of the expression of the cell cycle marker gene for G2-to-M transition in peanut roots suggested that AhCYCB1 expression was regulated by ABA. We also investigated the cooperative regulation of LRP initiation by ABA and indole-3-acetic acid (IAA). ABA treatment greatly reduced the effects of endogenous IAA on mature roots. The expression of the IAA polar transport gene AhAUX1 appeared to be regulated by ABA since ABA inhibited auxin-mediated LRP initiation by suppressing AhAUX-dependent auxin transport in peanut roots. We further examined the effect of ABA on the expression of DR5::GUS and AtAUX1 in the model plant Arabidopsis. The results of Arabidopsis were consistent with that of the peanut. © 2012 Elsevier GmbH.

Jia L.,Nanjing Agricultural University | Lou Q.,Nanjing Agricultural University | Jiang B.,Guangdong Academy of Agriculture science | Wang D.,Nanjing Agricultural University | Chen J.,Nanjing Agricultural University
Scientia Horticulturae | Year: 2014

Cucumis hytivus is a newly synthesized allotetraploid in which retrotransposons was strongly activated owing to allopolyploidization. In present study, the chromosomal distribution of LTR retrotransposons and their effects on expression of adjacent genes were observed by investigating the first four generations of C. hytivus. Fluorescent in situ hybridization (FISH) analysis revealed that LTR retrotransposons are distributed throughout all the chromosomes. The clusters on terminal regions indicated the high copy number of retrotransposons in C. hytivus. The extensive epigenetic changes (gene silencing and gene activation) were detected by cDNA-SSAP analysis. Totally, twenty transcripts subjected to gene expression alterations were sequenced, including 12 gene silencing and 8 gene activation. However, the silenced/activated transcripts consisted of known genes or putative proteins as well as new sequences that had no similarity to any known genes. Both gene silencing and activation mainly occurred in the early generations of allotetraploid. The interlaced distribution of retrotransposons and genes might lead to the transcriptional interference of retrotransposons on expression of their adjacent genes, which may contribute to the rapid genetic stabilization of newly formed allotetraploid. © 2014 Elsevier B.V.

Feng K.,South China Agricultural University | Feng K.,Key Laboratory of Chicken Genetics | Xue Y.,Guangdong Wens Food Co. | Wang F.,Guangdong Wens Food Co. | And 5 more authors.
Virus Genes | Year: 2014

Sixty-two strains of avian infectious bronchitis virus (IBV) were isolated from diseased chickens at different farms in southern China during 2011–2012, and 66.1 % of the isolated strains were associated with typical nephritis. Analysis of the S1 gene sequences amplified from the 62 isolated strains together with 40 reference strains published in Genbank showed nucleotide homologies ranging from 63.5 to 99.9 % and amino acid homologies ranging from 57.9 to 100 %. Phylogenetic analysis revealed that all Chinese IBV strains were clustered into six distinct genetic groups (I–VI). Most of the isolated strains belonged to group I, and the isolation of group V strains was increased compared with an earlier period of surveillance. Current vaccine strains used in China (H120, H52, W93, and Ma5) formed the group Mass which is evolutionarily distant from Chinese isolates. Alignment of S1 amino acid sequences revealed polymorphic and diverse substitutions, insertions, and deletions, and the S1 protein of major pandemic strains contained 540 amino acids with a cleavage site sequence of HRRRR or RRF(L/S)RR. Further analysis showed that recombination events formed a new subgroup. Taken together, these findings suggest that various IBV variants were co-circulating and undergoing genetic evolution in southern China during the observation period. Therefore, long-term continuing surveillance is significantly important for prevention and control of IBV infection. © 2014, Springer Science+Business Media New York.

Wu Z.-M.,Hebei Academy of Agricultural and Forestry science | Yan H.-B.,Hebei University of Economics and Business | Pan W.-L.,Hebei Academy of Agricultural and Forestry science | Jiang B.,Guangdong Academy of Agriculture science | And 5 more authors.
Australian Journal of Crop Science | Year: 2012

Plant lectins are widely distributed in the plant kingdom, and a number of cDNAs have been isolated from many plants. Here we reported the isolation an expression analysis of a cDNA from Pinellia pedatisecta named PPAb. The cDNA clone was obtained from the bulb using a reverse transcriptase-polymerase chain reaction (RT-PCR). The coding region of the gene is 777bp encoding 258 amino acids of a predicted 28.4 kDa molecular mass and with a pI of 8.32, and containing a 24 amino acid signal peptide. The gene shares 85.5% and 98.8% homology on the protein level with the lectin cDNA from P. pedatisecta and Arisaema heterophyllum, respectively. The deduced amino acid sequence contains the conserved features of mannose-binding lectins, including three mannose-binding sites (QXDXNXVXY). Southern blot analysis indicated that PPAb belongs to a multi-copy gene family, and Northern blot analysis revealed that the PPAb is preferentially expressed in the tuber. The insecticidal activity of PPAb against the tobacco aphids (Myzus nicotianae) was studied using transgenic tobacco plants expressing PPAb gene under the control of the constitutive CaMV 35S promoter. Northern blot assays revealed that lectin gene was expressed at various levels in the transgenic tobacco lines. Insect bioassays demonstrated that the ectopically expressing PPAb had significantly increased mortality, to tobacco aphids (Myzus nicotianae) fed on the transgenic lines when compared to wild type. These findings suggest that the PPAb is a suitable candidate protein for insect resistance in the control of various sap-sucking insects through a transgenic approach.

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