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Liu J.,Chinese University of Hong Kong | Cai Y.-Z.,Chinese University of Hong Kong | Cai Y.-Z.,China National Seed Group Co. | Wong R.N.S.,Hong Kong Baptist University | And 5 more authors.
Journal of Agricultural and Food Chemistry

Caffeoylquinic acids and lignans in the crude extracts of both roots and seeds from different burdock (Arctium lappa L.) genotypes were simultaneously characterized and systematically compared by LC-MS and matrix-assisted laser desorption/ionization quadrupole ion trap time-of-flight mass spectrometry (MALDI-QIT-TOF MS), and their antioxidant activities were also investigated. A total of 14 lignans were identified in burdock seeds and 12 caffeoylquinic acids in burdock roots. High levels of caffeoylquinic acids were also detected in burdock seeds, but only trace amounts of lignans were found in burdock roots. Burdock seeds contained higher concentrations of lignans and caffeoylquinic acids than burdock roots. Quantitative analysis of caffeoylquinic acids and lignans in roots and seeds of various burdock genotypes was reported for the first time. Great variations in contents of both individual and total phenolic compounds as well as antioxidant activities were found among different genotypes. Burdock as a root vegetable or medicinal plants possessed considerably stronger antioxidant activity than common vegetables and fruits. © 2012 American Chemical Society. Source

Liu F.,Chinese Academy of Agricultural Sciences | Zhang X.,China National Seed Group Co. | Lu C.,Chinese Academy of Agricultural Sciences | Zeng X.,Chinese Academy of Agricultural Sciences | And 3 more authors.
Journal of Experimental Botany

Plant non-specific lipid-transfer proteins (nsLTPs) are small, basic proteins present in abundance in higher plants. They are involved in key processes of plant cytology, such as the stablization of membranes, cell wall organization, and signal transduction. nsLTPs are also known to play important roles in resistance to biotic and abiotic stress, and in plant growth and development, such as sexual reproduction, seed development and germination. The structures of plant nsLTPs contain an eight-cysteine residue conserved motif, linked by four disulfide bonds, and an internal hydrophobic cavity, which comprises the lipid-binding site. This structure endows stability and increases the ability to bind and/or carry hydrophobic molecules. There is growing interest in nsLTPs, due to their critical roles, resulting in the need for a comprehensive review of their form and function. Relevant topics include: nsLTP structure and biochemical features, their classification, identification, and characterization across species, sub-cellular localization, lipid binding and transfer ability, expression profiling, functionality, and evolution. We present advances, as well as limitations and trends, relating to the different topics of the nsLTP gene family. This review collates a large body of research pertaining to the role of nsLTPs across the plant kingdom, which has been integrated as an in depth functional analysis of this group of proteins as a whole, and their activities across multiple biochemical pathways, based on a large number of reports. This review will enhance our understanding of nsLTP activity in planta, prompting further work and insights into the roles of this multifaceted protein family in plants. © 2015 The Author. Source

Qiao J.,Huazhong Agricultural University | Ma C.,China National Seed Group Co. | Wimmelbacher M.,Friedrich - Alexander - University, Erlangen - Nuremberg | Bornke F.,Friedrich - Alexander - University, Erlangen - Nuremberg | Luo M.,Huazhong Agricultural University
Plant and Cell Physiology

Chloroplast development requires the coordinated action of various proteins, many of which remain to be identified. Here, we report two novel genes, Mesophyll-cell RNAi Library line 7 (MRL7) and MRL7-Like (MRL7-L), that are involved in this process. An Arabidopsis knock-down transgenic plant (MRL7-RNAi) with delayed-greening phenotype was isolated from an RNA interference (RNAi) transformant library. Cotyledons and young leaves of MRL7-RNAi were pale in seedlings and gradually greened as the plant matured, while a knock-out in the MRL7 gene was seedling lethal. The MRL7 protein was shown to co-localize with a marker protein for nucleoids in chloroplasts, indicative of a role for the protein in chloroplast nucleic acid metabolism. Accordingly, chloroplast development was arrested upon loss of MRL7 function and the expression of plastid-encoded genes transcribed by plastid-encoded RNA polymerase (PEP) was significantly reduced in MRL7 knock-down and knock-out plants. A paralog of MRL7 (MRL7-L) was identified in the Arabidopsis genome. Both MRL7 and MRL7-L are only found in land plants and encode previously uncharacterized proteins without any known conserved domain. Like MRL7, knock-down of MRL7-L also resulted in a virescent phenotype, and a similar effect on plastid gene expression. However, the MRL7-L protein was localized to the chloroplast stroma. Taken together, our data indicate that the two paralogous proteins MRL7 and MRL7-L have essential but distinct roles during early chloroplast development and are involved in regulation of plastid gene expression. © 2011 The Author. Source

Chen H.,Peking University | Chen H.,Shenzhen Institute of Crop Molecular Design | He H.,Peking University | He H.,Shenzhen Institute of Crop Molecular Design | And 5 more authors.
Current Opinion in Plant Biology

Breeding by design has been an aspiration of researchers in the plant sciences for a decade. With the rapid development of genomics-based genotyping platforms and available of hundreds of functional genes/alleles in related to important traits, however, it may now be possible to turn this enduring ambition into a practical reality. Rice has a relatively simple genome comparing to other crops, and its genome composition and genetic behavior have been extensively investigated. Recently, rice has been taken as a model crop to perform breeding by design. The essential process of breeding by design is to integrate functional genes/alleles in an ideal genetic background, which requires high throughput genotyping platforms to screen for expected genotypes. With large amount of genome resequencing data and high-throughput genotyping technologies available, quite a number of genomics-based genotyping platforms have been developed. These platforms are widely used in genetic mapping, integration of target traits via marker-assisted backcrossing (MABC), pyramiding, recurrent selection (MARS) or genomic selection (GS). Here, we summarize and discuss recent exciting development of rice genomics-based genotyping platforms and their applications in molecular breeding. © 2013 Elsevier Ltd. Source

Jiang J.,Huazhong Agricultural University | Mou T.,Huazhong Agricultural University | Yu H.,China National Seed Group Co. | Zhou F.,China National Seed Group Co.

Background: Blast disease caused by the fungal pathogen Magnaporthe oryzae is one of the big problems in rice production in China, especially for high yield hybrid varieties made from a two-line system in which thermo-sensitive genic male sterile (TGMS) lines are used. In this study, we report the introgression of a rice blast resistance gene Pi2 from VE6219 into C815S, an elite rice TGMS line, leading to the development of blast resistant TGMS lines through marker assisted selection (MAS) and phenotypic selection approaches. Results: Four new TGMS lines with blast resistance gene Pi2 were developed from C815S (an elite TGMS line susceptible to the blast, used as recurrent parent) and VE6219 (a blast resistant line harboring Pi2, used as donor parent). The pathogenicity assays inoculated with 53 blast prevalent isolates in glasshouse showed that the blast resistant frequency of the four TGMS lines was 94.3%-98.1% that is equivalent to blast resistant donor parent VE6219. The field evaluation of the new lines and hybrids made from them at a blast epidemic site also showed high resistant levels against the blast. The genetic background of the newly developed TGMS lines were examined using a whole-genome single nucleotide polymorphism (SNP) array (RICE6K) that turned out more than 83% of the genomic markers were derived from the recurrent parent. The critical temperature points of fertility-sterility alteration of the new TGMS lines were between 22°C and 23°C of daily mean temperature, which is similar to that of C815S. The complete male sterility under natural growth conditions at Wuhan last more than 80 days. Their agronomic and grain quality traits meet the requirement for two-line hybrid rice production. Conclusions: The broad-spectrum and durable rice blast resistant gene Pi2 was introgressed into the elite TGMS line C815S background. The newly developed TGMS lines can be practically used for two-line hybrid rice breeding and must play an important role in sustainable rice production in China. © 2015, Jiang et al.; licensee Springer. Source

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