Leyuan Ma

Shandong Agricultural University, T’ai-an-shih, Shandong Sheng, China

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Publications (4)7.82 Total impact

  • Hui Hao · Leyuan Ma · Hongzi Cong · Qiang Li · Xiyan Yu
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    ABSTRACT: Lycopene Beta-cyclase (LCY-B) is thought to play a critical role in Beta-carotene synthesis in fruit. A full-length cDNA clone encoding Lycopene Beta-cyclase was isolated from muskmelon (Cucumis melo L.) by RT-PCR and RACE. The clone, designated CmLcyb1, contains 1871 nucleotides, with an open reading frame of 1512 nucleotides. The deduced 504-amino-acid sequence showed high identities with other plant Lycopene Beta-cyclases. Real time quantitative RT-PCR analysis indicated that CmLcyb1 was expressed in all tissues and organs of muskmelon inbred M01-3 with white mesocarp and, 'Homoka', an orange mesocarp cultivar. The expression levels of CmLcyb1 in roots, stems, leaves and flowers in the two genotypes differed little. The expression level was highest in mature fruit of 'Homoka' and was much higher than that in mature fruit of M01-3. Moreover, the mRNA level of CmLcyb1 was very low in fruits before fruit-size fixation and increased dramatically in the size-fixed fruits of these two genotypes. The mRNA levels of CmLcyb1 during fruit development of 'Homoka' were all higher than those of M01-3. Interestingly, Beta-carotene content showed almost the same change trend as mRNA levels during fruit development in these two genotypes, suggesting that Beta-carotene accumulation may be linked to the CmLcyb1 transcript level in muskmelon fruit.
    No preview · Article · May 2012 · Gene
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    ABSTRACT: Nitrate reductase is a key enzyme in the overall process of nitrate assimilation by plants. A full-length cDNA clone encoding nitrate reductase (NR; EC was isolated from cucumber (Cucumis sativus L.) by RT-PCR and RACE techniques. The NR of cucumber (CsNR), a full-length cDNA sequence of 3032 bp contains an open reading frame of 2748 bp encoding 915 amino acids. The deduced 915 amino acid sequence showed high identities with NR from other plants. Quantitative real-time PCR analysis indicated that CsNR expression was different in root, stem, leaf, flower and mature fruit tissues. CsNR transcript level and nitrate reductase activity (NRA) was down-regulated and the change in NO(3) (-) concentration showed a negative trend with NRA in leaves when subjected to the 182 mM NO(3) (-) treatment. However, the CsNR transcript level was up-regulated in roots by 182 mM NO(3) (-) treatment. Furthermore, NRA in roots lagged behind CsNR expression and there was no obvious lag of NRA in leaves. This study found that in roots, there was no obvious relationship between NRA and NO(3) (-) content. These results indicated that NRA was not only controlled by the level of CsNR mRNA and there was an obvious negative relationship between NO(3) (-) content and NRA in leaves but not in roots.
    No preview · Article · Jul 2011 · Molecular Biology Reports
  • Wenqian Zhang · Hui Hao · Leyuan Ma · Cong Zhao · Xiyan Yu
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    ABSTRACT: Tetraploid muskmelon plants were induced successfully from diploid Cucumis melo inbred M01-3 (2n=24) by colchicine. The morphological characteristics and fruit qualities of diploid and tetraploid muskmelons were investigated. The results showed that the leaves and flowers of the tetraploid plants were markedly larger, the plants were obviously higher, and the stems were thicker than those of the diploid plants. Transmission electron microscope observation revealed that the numbers of chloroplast, granule and grana, and the length of chloroplast and granule of the tetraploid plant leaves were significantly more or longer than those of the diploid plants. The soluble solid, soluble sugar and vitamin C contents in the tetraploid fruit were distinctly higher than those in the diploid fruit. The weight of the tetraploid fruit was 30% heavier than that of the diploid fruit. And the seeds from the tetraploid plants were broader and thicker than those from the diploid plants. Together, our results suggest that the tetraploid muskmelon exhibited better agronomical characteristics than the diploid muskmelon and the tetraploid muskmelon could be used as the improved variety and a potential germplasm for the development of triploid fruit.
    No preview · Article · Jun 2010 · Scientia Horticulturae
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    ABSTRACT: To unravel the roles of sucrose phosphate synthase (SPS) in muskmelon (Cucumis melo L.), we reduced its activity in transgenic muskmelon plants by an antisense approach. For this purpose, an 830 bp cDNA fragment of muskmelon sucrose phosphate synthase was expressed in antisense orientation behind the 35S promoter of the cauliflower mosaic virus. The phenotype of the antisense plants clearly differed from that of control plants. The transgenic plant leaves were markedly smaller, and the plant height and stem diameter were obviously shorter and thinner. Transmission electron microscope observation revealed that the membrane degradation of chloroplast happened in transgenic leaves and the numbers of grana and grana lamella in the chloroplast were significantly less, suggesting that the slow growth and weaker phenotype of transgenic plants may be due to the damage of the chloroplast ultrastructure, which in turn results in the decrease of the net photosynthetic rate. The sucrose concentration and levels of sucrose phosphate synthase decreased in transgenic mature fruit, and the fruit size was smaller than the control fruit. Together, our results suggest that sucrose phosphate synthase may play an important role in regulating the muskmelon plant growth and fruit development.
    No preview · Article · Feb 2010 · Biochemical and Biophysical Research Communications