Jun Xiong

Fujian Agriculture and Forestry University, Min-hou, Fujian, China

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Publications (17)6.09 Total impact

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    ABSTRACT: To explore the molecular mechanism of allelopathic rice in response to low nitrogen (N) supply or accompanying weed stress, allelopathic rice PI 312777 and its counterpart Lemont were grown under low N supply or co-cultured with barnyardgrass [Echinochloa crus-galli (L.) Beauv.] in hydroponics. The suppression subtractive hybridization (SSH) technique was employed to isolate the up-regulated genes in the treated rice accession. The results indicated that the expression of the genes associated with N utilization was significantly up-regulated in allelopathic rice PI 312777, and the higher efficiency of N uptake and its utilization were also detected in PI 312777 than that in Lemont when the two rice accessions were exposed to low N supply. This result suggested that the allelopathic rice had higher ability to adapt to low N stress than its non-allelopathic counterpart. However, a different response was observed when the allelopathic rice was exposed to accompanying weed (barnyardgrass) co-cultured in full Hoagland solution (normal N supply). It showed that the expression of the genes associated with allelochemical synthesis and its detoxification were all up-regulated in the allelopathic rice when co-cultured with the target weed under normal N supply. The results suggested that the allelopathic rice should be a better competitor in the rice-weed co-culture system, which could be attributed to increasing de novo biosynthesis and detoxification of allelochemicals in rice, consequently resulting in enhanced allelopathic effect on the target and preventing the autotoxicity in this process. These findings suggested that the accompanying weed, barnyardgrass is not only the stressful factor, but also one of the triggers in activating allelopathy in rice. This implies that the allelopathic rice is sensible of the existing target in chemical communication. KeywordsAllelopathy-Barnyardgrass-Gene expression-Low nitrogen-Plant defense-Rice
    No preview · Article · Jul 2010 · Plant Growth Regulation
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    ABSTRACT: Crop allelopathy is a promising and environmentally friendly method in weed control; however, the inducible genetic trait for allelopathy in the suppression of weeds needs to be overcome for practical use. Further study needs to be directed to this end to elucidate the molecular genetics and its physiologic mechanism. In this paper, the authors review recent advances in the investigation of rice allelopathy and its molecular regulatory mechanism, especially in responses to stressful conditions including biotic and abiotic factors in China. Previous studies show that rice allelopathy could be enhanced when the rice accession was exposed to stressful conditions, and further analysis by the transcriptomics and proteomics approaches conducted in our laboratory indicated that the increase in allelopathic potential of rice, when exposed to the stresses, was attributed to increased expression level of genes involved in phenolic synthetic metabolism. The increasing phenolic compounds have been confirmed as the main allelochemicals and they jointly act to suppress the target, especially in responses to stressful condition, but it seems to be the primary effect in phenolic allelopathy. We still wonder how the exudates from rice root, which were released into rhizosphere soil, are transformed by soil microorganism to produce the higher secondary effect of phenolic allelopathy in the suppression of weeds. Therefore, the authors suggest that rhizosphere biologic properties of allelopathy in rice and its mechanism are being the key research areas in the world now, and systems biology and its approaches, such as metagenomics and metaproteomics, would be helpful to reveal the process and its molecular ecological mechanism regarding rhizospheric biology of rice allelopathy. KeywordsAllelopathy-rice-molecular mechanism-stress
    No preview · Article · Jun 2010

  • No preview · Article · Jan 2010 · CHINESE JOURNAL OF ECO-AGRICULTURE

  • No preview · Article · Dec 2009 · CHINESE JOURNAL OF ECO-AGRICULTURE
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    ABSTRACT: To investigate the molecular mechanism of metabolism in rice (Oryza sativa L.) source organs, protein expression pattern in flag leaves of rice cultivar Jinhui 809, a cultivar with large panicle and high seed-setting percentage, was analyzed during grain-filling period. Using two-dimensional electrophoresis and mass spectrometry, 17 protein spots with differential expression were detected. Among them, 3 protein spots had the most expression amount from early to medium stage, 9 protein spots for middle–late stages, and 4 protein spots for late stage. In addition, 1 protein spot had two-expression peaks at early and late stages of grain filling. Twelve differential proteins were identified with MALDI-TOF/MS analysis and database searching. They were involved in biosynthesis and degradation, carbohydrate transportation, antioxidation reaction, hormone metabolism, cytoskeleton construction, and tissue maturation. Ribose/galactose/methyl galactoside importing ATP-binding protein 1 participated in photosynthate transportation from leaf to grain in early and medium stages. Auxin-responsive protein IAA27 influenced photosynthate transportation through regulating the activity of ATPase. N-acetyl-glutamate semialdehyde dehydrogenase delayed leaf senescence through regulating polyamine metabolism in late stage. In addition, glutathione S-transferase and superoxide dismutase played an important role in plant detoxification and fighting against active oxygen damage at late stage of grain filling.
    No preview · Article · Jan 2009 · Acta Agronomica Sinica
  • Wen-Xiong LIN · Gao-Jing YU · Jun XIONG · Ting CHEN

    No preview · Article · Jan 2009 · CHINESE JOURNAL OF ECO-AGRICULTURE
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    ABSTRACT: By using a population of 123 F12 lines (recombinant inbred lines, RILs) derived from a cross between India variety Dular and Japanica variety Lemont, an analysis of quantitative trait loci (QTL) was conducted for the flag leaf chlorophyll content of rice. The chlorophyll content was determined by SPAD-502 in 2005 and 2006, respectively, and software QTLMapper 1.6 was applied to analyze the QTL, including the additive and epistatic effects and the QTL interactions with environment for chlorophyll content. A total of ten QTL showing additive effects on chlorophyll content (Chl) were detected, which accounted for 73.51% of the phenotypic variation. The percentage of phenotypic variation explained by single QTL was 2.08%-20.14%, and the interactions of 6 QTLs with environment (AE) were significant. Epistasis analysis indicated that there existed 13 significant additive x additive interactions on chlorophyll content, 6 pairs of which were significant in additive x additive interactions with environment (AAE).
    No preview · Article · Jan 2009 · Ying yong sheng tai xue bao = The journal of applied ecology / Zhongguo sheng tai xue xue hui, Zhongguo ke xue yuan Shenyang ying yong sheng tai yan jiu suo zhu ban
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    ABSTRACT: The allelopathy-competition separation (ACS) based approach was used to explore the biointerference relationship between rice accessions and barnyardgrass exposed to different nitrogen (N) supplies in hydroponics. Rice accession PI312777 exhibited high allelopathic potential to suppress the growth of accompanying weeds, especially when the culture solution had low N content. The non-allelopathic rice Lemont showed an opposite result. Additionally, subtractive hybridization suppression (SSH) was used to construct a forward SSH-cDNA library of PI312777 to investigate gene expression profiles under low N treatment. A total of 35 positive clones from the SSH-cDNA library were sequenced and annotated. According to the function category, 24 genes were classified into five groups related to primary metabolism, phenolic allelochemical synthesis, plant growth/cell cycle regulation, stress response/signal transduction, and protein synthesis/degradation. Among them, two up-regulated genes that encode PAL and cytochrome P450 were selected. Their transcript abundance at low N level was compared further between the allelopathic rice and its counterpart by utilizing real-time quantitative polymerase chain reaction (qRT-PCR). The transcription levels of the two genes increased in both rice accessions when exposed to low N supply, but PI312777 at a higher magnitude than Lemont. At 1, 3, and 7 days of the treatments, the corresponding relative expression levels of PAL were 11.38, 4.83, and 3.57 fold higher in PI312777 root, but there were 1.15, 2.74, and 2.94 fold increases for Lemont, compared with the control plants fed with regular nutrient. The same trend was found for cytochrome P450. These findings suggest that the stronger ability of PI312777 to suppress target weeds, especially in low N nutrient conditions, might be attributed to the stronger activation of the genes that function in de novo synthesis of allelochemicals.
    No preview · Article · Jun 2008 · Journal of Chemical Ecology
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    ABSTRACT: To reveal the molecular mechanism of metabolism in rice (Oryza sativa L.) leaf sheath, differential expression of proteome in rice leaf sheath was investigated with a large panicles and high grain-setting rate cultivar, i.e., Jinhui 809. Through the method of differential proteomics, 23 proteins were detected, and 11 proteins were identified to be the functional proteins. These functional proteins were classified into 6 categories according to their dynamic patterns of expression during grain-filling stage. The first class, such as oxaloacetate decarboxylase alpha subunit, showed down-regulation during grain filling. The second class, which included ribulose bisphosphate carboxylase small chain and ADP-ribosylation factor 1, exhibited up-regulation at first and then down-regulation. The third class, such as auxin response factor, zinc finger, C3HC4 type family protein, vacuolar proton-ATPase, and ribulose bisphosphate carboxylase/oxygenase activase, was down-regulation first and then up-regulation and down-regulation alternatively. The fourth class included Rubisco binding-protein alpha subunit, showing an expression pattern of up and down-regulation alternatively twice during grain filling. The fifth class performed a decreasing at first and then gradually increasing expression pattern. This class included class II metallothionein-like protein 1A and geranylgeranyl diphosphate synthase. The sixth class was protein kinase family protein performing a gradually increasing expression pattern. These 6 classes of proteins were involved in photosynthesis, hormone regulation, substance transportation, resistant response to plant senescence, and cell signal transduction in leaf sheath, respectively. They regulated the transition of sink to source together.
    No preview · Article · Apr 2008 · Acta Agronomica Sinica
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    ABSTRACT: To investigate the feasibility of using exogenous salicylic acid (SA) to regulate the allelopathic weed suppression of rice, this paper studied the effects of different concentrations exogenous SA on the weed-suppression and physiological-biochemical characteristics of allelopathic rice PI312777, and the relative expression quantity of gene ZB8 in the rice by real time quantitative RT-PCR (FQ-PCR). The results showed that exogenous SA induced the enhancement of the allelopathic potential of donor rice in suppressing target weed plants, and this inducing effect was SA dose and treatment time dependent. After foliar spraying SA, the inhibitory effect of PI312777 on barnyardgrass increased significantly, and the root vigor and superoxide dismutase (SOD) and peroxidase (POD) activities of PI312777 increased, while its catalase (CAT) activity decreased. The reverse was true for the target weed barnyardgrass. At the same time, the phenylalanine ammonialyase (PAL) activity of PI312777 increased significantly, leading to an increase of the total content of phenols. Among the test concentrations of SA, 0.2 mmol x L(-1) had the best inducing effect, under which, the relative expression quantity of ZB8 increased first and decreased then, with a peak at 24 hours after treatment.
    No preview · Article · Mar 2008 · Ying yong sheng tai xue bao = The journal of applied ecology / Zhongguo sheng tai xue xue hui, Zhongguo ke xue yuan Shenyang ying yong sheng tai yan jiu suo zhu ban
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    ABSTRACT: The defense characteristics of allelopathic rice accession PI312777 and its counterpart Lemont induced by exogenous salicylic acid (SA) to suppress troublesome weed barnyardgrass (BYG) were investigated using the methods of suppression subtractive hybridization (SSH) and real-time fluorescence quantitative PCR (qRT-PCR). The results showed that exogenous SA could induce the allelopathic effect of rice on BYG and this inducible defense was SA dose-respondent and treatment time-dependent. PI312777 exhibited higher inhibitory effect than Lemont on BYG after treated with different concentrations of SA. The activities of cell protective enzymes including SOD, POD and CAT in the BYG plants co-cultured with PI312777 treated by SA were highly depressed compared with the control (co-cultured with rice without SA-treatment). Similar but lower depression on these enzymes except for CAT was also observed in the BYG plants when co-cultured with Lemont treated by SA. It is therefore suggested that allelopathic rice should be more sensitive than non-allelopathic rice to exogenous SA. Seventeen genes induced by SA were obtained by SSH analysis from PI312777. These genes encode receptor-kinase proteins, ubiquitin carrier proteins, proteins related to phenylpropanoid metabolism, antioxidant related proteins and some growth-mediating proteins. The differential expressions of these genes were validated in part by qRT-PCR in the two rice accessions. Our work elucidated that allelopathic rice possesses an active chemical defense and auto-detoxifying enzyme system such as the up-regulated enzymes involved in de novo biosynthesis of phenolic allelochemicals and the glutathione-S-transferase (GST) associated with xenobiotic detoxification.
    No preview · Article · Mar 2008 · Plant Growth Regulation
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    ABSTRACT: With the soils cropped Rehmannia glutinosa for one and two years as test materials, this paper studied the variations of microbial flora and enzyme activities in rhizosphere. The results showed that with increasing year of cropping, the numbers of bacteria and fungi in rihzosphere had a slight decrease. In the soil successively cropped R. glutinosa for two years, the number of actinomycetes in rihzosphere was 4 times higher, the ammonifier, aerobic azotobacter, sulphate reducer, denitrifier, and anaerobic cellulose-decomposer increased by 25.99, 45.39, 11.43, 1.36, and 1.43 folds, respectively, while aerobic cellulose-decomposer reduced by 86.74%, compared with those in the soil cropped R. glutinosa for one year. The root exudates of successively cropped R. glutinosa increased the activities of urease, polyhphenol oxidase, sucrase, protease and cellulase in rhizosphere by 62.87%, 9.43%, 47.91%, 139.62% and 31.33%, respectively, but inhibited the activity of catalase. The findings suggested that successive cropping R. glutinosa would destroy the balance of rhizosphere soil microbial flora.
    No preview · Article · Jan 2008 · Ying yong sheng tai xue bao = The journal of applied ecology / Zhongguo sheng tai xue xue hui, Zhongguo ke xue yuan Shenyang ying yong sheng tai yan jiu suo zhu ban
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    Lihua Shen · Jun Xiong · Wenxiong Lin
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    ABSTRACT: This article reviews advances in the investigation of rice allelopathy with particular reference to China. We first evaluated several bioassay methods commonly used in laboratory bioassay. Then we reviewed the present status of the investigation on quantitative genetics, quantitative trail loci (QTLs) mapping, genetic diversity, and molecular ecological properties of allelopathy in rice. It was apparent that allelopathy was characterized by quantitative inheritance. Several QTLs for allelopathic effect on the target weed plants such as barnyard grass have been determined and mainly located on chromosome 1, 2, 3, 5, 8, 9 and 12, which were significantly mediated by external environment. The increased allelopathic potential in rice exposed to stresses was due to the increased expression of genes involved in synthetic metabolism of phenolic compounds and the decreased expression of enzymes was associated with terpenoid synthetic metabolism.
    Preview · Chapter · Dec 2007
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    ABSTRACT: Differential expression of the key genes controlling phenolic metabolism in allelopathic and non-allelopathic rice accessions was investigated under two nitrogen supply levels (lower and normal) using fluorescence quantitative-polymerase chain reaction (FQ-PCR) (Figs.2, 3). The results indicated that 9 key enzyme genes concerned were mediated by lower nitrogen level (Table 2). All of the nine genes (Table 1, Fig.4), were up-regulated by 1.9-5.4 times of the relative gene expression amounts in allelopathic rice accession, 'PI312777' under the lower nitrogen condition compared with their controls, of which PAL gene showed the highest relative gene expression amount with 5.4 times of the relative gene expressions compared with the control, while in non-allelopathic rice Lemont, seven genes were down-regulated by 29%-72% under lower nitrogen supplies compared with their controls and only two genes, i.e., phenylalanine ammonia-lyase and cinnamoyl-CoA genes were up-regulated, which however were a decrease of 22% and 74% over those in allelopathic rice accession (Table 2). These findings strongly suggest that the increase of allelopathic potential induced by 1/4 nutrient stress was responsible for enhanced phenolic compound synthesis metabolism.
    No preview · Article · Nov 2007 · Zhi wu sheng li yu fen zi sheng wu xue xue bao = Journal of plant physiology and molecular biology
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    ABSTRACT: In this study, allelopathic rice accession PI312777 seedlings were grown on a paddy soil under near natural condition, and their root exudates were collected by using circulation method, with the solution collected from no seedlings- planted soil as the control. The ether extracts of the root exudates and soil solution were detected by GC-MS, and identified with the mass spectral database of NIST and WILEY Library. The results showed that there were 36 compounds in the rice root exudates, including 9 terpenoids (peak area 10.97%), 8 phenols or quinones (5.87%), 6 esters (10.68%), 3 aldehydes or ketones (1.44%), 4 heterocycles (68.04%), 2 alcohols (1.23%), 2 ethers (0.57%), and 2 others (1.20%). A distinctly similar structure was observed among the terpenoids and among the phenols or quinones. In the soil solution, 39 compounds were detected, and 7 of them were the same of the root exudates. The difference of the compounds in rice root exudates and soil solution, and the possible allelopathic mechanisms of these compounds were discussed in this paper.
    No preview · Article · Jan 2006 · Ying yong sheng tai xue bao = The journal of applied ecology / Zhongguo sheng tai xue xue hui, Zhongguo ke xue yuan Shenyang ying yong sheng tai yan jiu suo zhu ban
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    ABSTRACT: In order to explore the bio-interference of allelopathic rice with barnyardgrass under different nitrogen supplies, a new bioassay method, i.e., allelopathy-competition separation based (ACS) approach was recommended in this study. The results indicated that ACS could be successfully used to distinguish the rice allelopathy from its resources competition in rice-weed co-culture system, and to evaluate its response characteristics under different N supplies. The test rice accession PI312777 had a higher ability in interfering target weed barnyardgrass (BYD), represented by its stable and higher ability in resources competition, as well as its increasing allelopathic potential in suppressing companion weed BYD when the N supply decreased in the co-cultured system. The reverse was true in the case of rice accession Lemont, which had a lower allelopathic potential under all N supply levels, and a lower ability in resources competition under normal or rich N supply. But, Lemont had an obviously increased ability in resources competition under lower N supply, which was considered as the result of econiche competition in rice-weed system.
    No preview · Article · Jun 2005 · Ying yong sheng tai xue bao = The journal of applied ecology / Zhongguo sheng tai xue xue hui, Zhongguo ke xue yuan Shenyang ying yong sheng tai yan jiu suo zhu ban
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    ABSTRACT: In this paper, a strong allelopathic rice variety PI312777 and a weak allelopathic rice variety Lemont were used as test materials, and the root exudates of two rice varieties grown in the media of sand and soil were respectively collected by using circulation system approach. The terpenoids in ether-extracts were detected by GC-MS, and characterized by spectrum database. The results showed that some terpenoids such as limonene oxide, limonene dioxide, carvone oxide, carveol, and cedrol were detected in the ether-extracts. Different rice varieties had the similar kinds of terpenoids, but their existing modes and quantities were different. The differences between different various cultural methods and between rice varieties were further discussed.
    No preview · Article · May 2005 · Ying yong sheng tai xue bao = The journal of applied ecology / Zhongguo sheng tai xue xue hui, Zhongguo ke xue yuan Shenyang ying yong sheng tai yan jiu suo zhu ban