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10 July 2015, Volume 29 Issue 4 Previous Issue    Next Issue
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Development of Specific DNA Markers for Detecting the Rice Blast Resistance Gene Alleles Pi2/9/z-t Li-xia HUA, Wen-juan WANG, Shen CHEN, Cong-ying WANG, Lie-xian ZENG, Jian-yuan YANG, Xiao-yuan ZHU, Jing SU 2015, 29(4): 305-310.  DOI: 10．3969/j．issn．1001G7216．2015．03．010 Abstract ( )   HTML ( )   Specific molecular markers for detecting the alleles of Pi2/Pi9/Piz-t, designated as Pi2SNP, Pi9SNP and Pizt-PA, respectively, have been successfully developed through sequence comparison method. These three specific markers can distinctly distinguish target genes from others mapped on Pi2/9 locus, which facilitate the molecular marker-assistant selection and the development of pyramiding cultivars combined with other allele R genes. Additionally, 101 main cultivars and breeding parents collected from different rice-planting areas have been diagnosed with these three specific markers, and the results showed that only 2 out of 101 cultivars carried Piz-t, but neither Pi2 nor Pi9 band had been detected. So far, it indicated that most of the main cultivars and breeding parents in China do not carry Pi2/Pi9/Piz-t. These results had provided important information for the application of Pi2/Pi9/Piz-t in the blast resistance breeding programs.

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Identification of OsFBX310bh6, A New Allele for Brown Hull in Rice Xia XU, Xiao-bo ZHANG, Yong-feng SHI, Hui-mei WANG, Qi-na HUANG, Bao-hua FENG, Xiao-hong LI, Dan GUO, Jian-li WU 2015, 29(4): 335-342.  DOI: 10．3969/j．issn．1001G7216．2015．04．001 Abstract ( )   HTML ( )   PDF (1190KB) ( )   A brown hull 6 (bh6) mutant of rice was isolated from an EMS-induced IR64 mutant bank. The brown pigments start to accumulate in the hulls after heading and reach a maximum level in mature seeds. The 1000-grain weight and panicle length of bh6 significantly decreased while other agronomic traits including plant height, number of productive panicles per plant, number of filled grains per panicle and seed-setting rate were largely similar to those of the wild-type IR64. Analysis of pigment contents indicated that the levels of total flavonoids and anthocyanin in bh6 were significantly increased. The brown hull phenotype was controlled by a single recessive gene on the long arm of chromosome 9. Sequencing analysis indicated that a single base substitution (G-A) at position 1013 was detected in the candidate gene (LOC_Os09g12150) encoding an F-box domain containing protein. Functional complementation using the wild-type allele could rescue the mutation. The mutation, designated as OsFBX310bh6, is a new allele of OsFBX310 functioning as an inhibitor of brown hull. Isolation of OsFBX310bh6 provides useful experimental materials and would facilitate the studies on mechanism of flavonoid metabolism in monocot plants.

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Subcellular Localization Analysis of Phosphatidylserine Synthase (OsSUI1) in Tobacco Mesophyll Cells Juan ZHAO, Shu-jing KANG, Yu-chun RAO, Zhen-nan QIU, Jie XU, Jiang HU, Guang-heng ZHANG, Da-li ZENG, Long-biao GUO, Qian QIAN, Li ZHU 2015, 29(4): 343-349.  DOI: 10．3969/j．issn．1001G7216．2015．04．002 Abstract ( )   HTML ( )   PDF (2375KB) ( )   SUI1 encodes a phosphatidylserine synthase. And its mutant sui1-1 exhibites a shortened uppermost internode and apartly sheathed panicle. On this basis, two vectors pMDC45-SOVT and pMDC201-SOV were constructed by the Gateway system, which responds to the N-terminal and C-terminal fusion GFP. To observe the subcellular localization of SUI1, tobacco leaves have been infected by Agrobacterium with destination vectors. The results showed that GFP-SUI1 fusion proteins positioned in the plasma membrane and nucleus, while SUI1-GFP were localized in the plasma membrane and the nuclear membrane. Moreover, the distribution of the two fusion proteins were not continuous in the plasma membrane. We speculate that SUI1 protein was localized in the plasma membrane and nuclear membrane of tobacco leaf cells because the target protein folding and transmembrane manner may be changed by the N-terminal fusion, affecting the correct position of the protein.

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Morphological Characteristics and Gene Mapping of a Novel Low Tiller Number and Erect Panicle Mutant in Rice (Oryza sativa L.) Hai-bo ZHANG, Dong-dong ZENG, Xiao-li JIN, Xi ZHENG, Chun-hai SHI 2015, 29(4): 350-356.  DOI: 10．3969/j．issn．1001G7216．2015．04．003 Abstract ( )   HTML ( )   PDF (1953KB) ( )   A novel rice mutant named ltep1 (low tiller number and erect panicle 1) was obtained from the wild type Nipponbare after EMS treatment. It was mainly characterized by erect panicles at the maturity stage with reduced tillers. The results showed that both rachis wall and culm wall in the ltep1 mutant were thicker than those in the wild-type plant, providing the mutant with stronger mechanical endurance. Genetic analysis indicated that the abnormal phenotype was controlled by a single recessive gene. By map-based cloning, ltep1 was mapped in a 160 kb region between two SSR markers, bep16 and RM25866, at the long arm of chromosome 10. Since no homologous gene had been found in this region, ltep1 might be a novel gene related to the development of rice panicle and tiller.

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Genetic Analysis and Mapping of a Dwarf and High-tillering Mutant bf370 in Rice Yun-gao HU, Guo-tao YANG, Lian-an GUO, Peng QIN, Yong-jun CHEN, Shi-gui LI 2015, 29(4): 357-362.  DOI: 10．3969/j．issn．1001G7216．2015．04．004 Abstract ( )   HTML ( )   PDF (1895KB) ( )   A dwarf and high-tillering mutant bf370 was obtained from the indica rice variety Hong’ai B by neutron radiation. Compared with the wild type, the mutant bf370 was characterized by dwarf plant and more tillers. The number of tillers in bf370 was about 200, which was 13 times more than that in the wild type. Genetic analysis indicated that this phenotype was controlled by a single recessive nuclear gene, which was mapped to a 398 kb region between the marker Indel 4 and Indel 10 on the long arm of chromosome 1 using the F2 mapping population generated from the cross between mutant bf370 and Nipponbare. Sequencing analysis showed a 66 nucleotide deletion in the second exon of D10, resulting in a 22 amino acids deletion in the predicted RPE65 domain of D10 protein in the bf370 mutant. Combined with the phenotype of other d10 mutants, the phenotype of bf370 was likely caused by a 66 nucleotide deletion in D10.

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Variations in Plant Type Traits and Their Relationship of Progeny Derived from the Cross Between Chinese Rice Variety and Japanese Rice Variety Hai XU, Yan-long GONG, Yuan-ye XIA, Zhi-qiang YAN, Hua-jie WANG, Liang TANG, Zheng-jin XU 2015, 29(4): 363-372.  DOI: 10．3969/j．issn．1001G7216．2015．04．005 Abstract ( )   HTML ( )   PDF (2000KB) ( )   Plant type improvement plays an important role in breeding of new rice varieties with high yield and good quality. A recombinant inbred lines (RIL) population, constructed by crossing Liaojing 5, the most representative rice cultivar with erect panicle type in Northeast China with Akita Komachi, the Japanese famous good quality rice variety with curved panicle type, were used as test material to investigate the variations in plant type traits in the progeny and their mutual relationship. The results showed that there was remarkable separation in plant type traits among RIL population, most of plant type traits accorded with inheritance of quantitative traits controlled by multi genes.These plant type traits could be recombined in the progeny, but the correlation between different plant type characters significantly differed. Similar to Akita Komachi, the RILs with higher plant height always characterized by long panicle, large panicle curvature, small leaf width, few number of branches, low grain density. However, the RILs with dwarf plant height tended to have short panicle, small panicle curvature, large leaf width, large number of branches, large grain density, similar to Liaojing 5. This phenomenon was related to some genes pleiotropy or linkage which controlled some plant type traits. Despite the low probability, the typical plant type characters of Chinese rice varieties and Japanese rice varieties could be combined with each other. Breeders could create new varieties with comprehensive characteristics of plant type through hybridization and direct selection, such as long-flag-leaf and short-dense-panicle type or dwarf and long panicle type.

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Identification of Molecular Marker Fragments Associated with Combining Ability for Quality Traits in Parents of Hybrid japonica Rice (Oryza sativa L.) Yang LIU, Er-bao LIU, Si-yuan ZENG, Wei PU, Qiang-ming LIU, Li-jun LIANG, Pei-rui LIU, Qi-meng ZHANG, De-lin HONG 2015, 29(4): 373-381.  DOI: 10．3969/j．issn．1001G7216．2015．04．006 Abstract ( )   HTML ( )   PDF (439KB) ( )   In order to improve rice quality combining ability of parental lines more efficiently in hybrid japonica rice(Oryza sativa L.), SSR molecular marker fragment genotypes of elite combining ability for eight quality traits were identified by analyzing the data of combining ability and SSR markers in eleven cytoplasmic male sterile(CMS) lines and nine restorer lines. The eight quality traits investigated were brown rice rate (BRR), milled rice rate (MRR), head rice rate (HRR), percentage of chalky grain, chalkiness degree, alkali spreading value (ASV), gel consistency, and amylose contents. The 11 CMS lines and 9 restorer lines were genotyped using 152 pairs of SSR primers. Combining ability analysis was conducted using the data of 99 F1s made with NCII genetic design (11 CMS lines×9 restorer lines). A total of 49 SSR molecular marker fragment genotypes involving 27 molecular marker fragments were significantly associated with general combining ability of the 8 quality traits. 31 SSR molecular marker fragment genotypes on 14 chromosome arms were associated with elite combining ability for quality traits of parents; the remaining 18 molecular marker fragment genotypes were associated with unfavorable combining ability of quality traits of parents. Among the 49 molecular marker fragment genotypes, two were co-associated with four quality traits of parents, and two were each co-associated with three quality traits of parents, and eight were each co-associated with two quality traits of parents. The molecular marker fragment genotype RM542-80/105 on the long arm of chromosome 7 increased alkali spreading value in F1 by 37.0%, RM246-95/105 on the short arm of chromosome 1 decreased amylose contents in F1 by 23.8%, RM3754-80/90 on the long arm of the chromosome 8 increased the traits of BRR, MRR, HRR and ASV in F1 by 1.1%, 2.0%, 2.4% and 43.6%, respectively. The molecular marker fragment genotypes could be directly used for improving general combining ability of grain quality traits of parents in japonica rice.

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Effects of Rhizosphere Oxygen Concentration on Rice Grain Yield and Nitrogen Utilization Zhi-hua HU, Lian-feng ZHU, Yu-jiong LIN, Ji-jie HU, Jun-hua ZHANG, Qian-yu JIN 2015, 29(4): 382-389.  DOI: 10．3969/j．issn．1001G7216．2015．04．007 Abstract ( )   HTML ( )   PDF (1244KB) ( )   Hydroponic experiments were conducted to reveal the effect of rhizosphere oxygen concentration on rice grain yield and nitrogen absorption and utilization with IR45765-3B(deep water rice), Zhongzheyou 1 (lowland rice)and Zhonghan 221 (upland rice) as material at four rhizosphere oxygen concentration levels, 1.0 mg/L (T1, hypoxia),3.0 mg/L (T2),5.5 mg/L (T3) and 7.5 mg/L(T4, saturated oxygen concentration).The results showed that under various rhizosphere oxygen concertrations the grain yield and dry matter accumulation significantly differed among cultivars, and followed a trend of T2>T1>T3>T4. For IR45765-3B and Zhonghan 221, the impact on grain yield was mainly due to grain number per panicle and seed-setting rate. For Zhongzheyou 1, it was due to the above two factors and effective panicle number. In case of nitrogen accumulation and utilization, the nitrogen absorption under T1 and T2 was enhanced during early growth stage. Aeration could increase N accumulation during late grain filling stage,but hinder N transferring to grain under excessive oxygen concentration. In addition, nitrogen utilization efficiency (NUE) in T2 was the highest, 6.9%,12.8%,13.8% higher than those in T1, meanwhile N dry matter production efficiency was enhanced due to rhizosphere aeration during vegetative growth stage. In all, rhizosphere oxygen concentration of 3.0mg/L effectively enhance grain yield and N absorption and utilization of three rice genotypes.

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Root Traits Affecting Nitrogen Efficient Absorption in Rice Genetic Populations Chen CHEN, Bin YANG, Zheng-kang ZHU, Wen-ya CAO, Gang LUO, Juan ZHOU, Xiang-ju WANG, Xiao-feng YU, Qiu-mei YUAN, Jun ZHONG, Yi WANG, Jian-ye HUANG, Yu-long WANG, Gui-chun DONG 2015, 29(4): 390-398.  DOI: 10．3969/j．issn．1001G7216．2015．04．08 Abstract ( )   HTML ( )   PDF (707KB) ( )   To investigate the relationship between root traits and nitrogen accumulation in rice cultivars, a total of 114 chromosome single segment substitution lines (CSSSLs) were solution-cultured in 2010 and 2011. On the basis of nitrogen accumulation per plant and yield per plant at maturity, the CSSSLs were clustered by MinSSw method into six types (namely A,B,C,D,E and F by nitrogen accumulation per plant from low to high). The results shows that: 1)There was a significant difference among all tested lines in N accumulation per plant, the variation ranged from 0.32 g to 0.91 g. The highest N accumulation was 2.58 folds of the lowest. 2)Both N accumulation and nitrogen use efficiency for grain production were important contributors to yield formation, but the former exhibited higher contribution. With higher nitrogen accumulation, grain yield tended to increase, but nitrogen accumulation types and grain yield types were not always associated. 3)Higher nitrogen accumulation is an important basis of higher yield, but yield was also affected by other factors. 4)The differences in root activity traits (including the total root absorption area, the root active absorption area and the root activity) among rice cultivars were limited, but the root morphological traits(including total length of adventitious roots, root dry weight, the maximum root length and plural root length) and the ratio of shoot to root showed significant differences. The total length of adventitious roots per plant, root dry weight per plant, the maximum root length, plural root length and the ratio of shoot to root of higher nitrogen efficiency and yield types were significantly larger than those of lower nitrogen efficiency and yield types. 5) Correlation analysis, principal component analysis and path analysis revealed that main traits influencing nitrogen accumulation in the rice population were root dry weight per plant, the ratio of shoot to root at heading stage, the maximum root length and total length of adventitious roots per plant. Improving the root morphological traits through genetic approaches might significantly enhance nitrogen accumulation efficiency in rice plants.

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Effects of Different Nitrogen, Phosphorus and Potassium Treatments on Rice Yield, Quality, Nutrient Absorption-Utilization and Economic Benefit of Zhongzheyou 1 in Central Zhejiang Province,China Zuo-zhen DONG, Liang-huan WU, Jie CHAI, Yuan-li CHEN, Yue-zhong ZHU 2015, 29(4): 399-407.  DOI: 10．3969/j．issn．1001G7216．2015．04．009 Abstract ( )   HTML ( )   PDF (438KB) ( )   A field experiment was conducted from 2008 to 2010 to reveal the effects of different nitrogen (N), phosphorus (P) and potassium (K) treatments on rice yield, quality, nutrient absorption-utilization and economic benefit by using the “3414” fertilizer experiment design. Results showed that N, P and K fertilization significantly increased rice grain yield, and the effect of combined application of those three fertilizers on grain yield was better than the combination of any of two fertilizers; the yield-increasing effect followed the order of N>K>P. The highest yield was obtained in N3P2K2treatment, being 8746 kg/hm2. N fertilization improved gel consistency (GC), protein content (PC) and total amino acid content, meanwhile reduced alkali spreading value (ASV); P fertilization improved PC; K fertilization improved GC, ASV and PC. The rice total nutrient (N, P2O5, K2O) accumulation and nutrient absorption rates per 100 kg seeds increased with increasing fertilizer application rates, while the nutrient absorption and utilization efficiency and agronomic efficiency decreased with the increase of applied fertilizer rates. The absorption and utilization efficiency for N, P and K were 25.2%, 38.3% and 36.0%, respectively. The economic benefits were increased by 21.1%, 20.3%, 20.3% and 22.4% for N2P2K2, N2P3K2, N2P2K1 and N3P2K2 treatments, respectively, compared with N0P0K0 treatment. According to the fertilizer effect equations, the N, P(P2O5 ) and K( K2O) application rates for the highest grain yield were 258.8 kg/hm2,39.3 kg/hm2 and 100.8 kg/hm2, respectively.

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Use of GGE Biplots in the Yielding Ability, Stability and Adaptation Evaluation for the Varieties in the Rice Regional Trials Lei WANG, Ben-yi CHENG, Zhi-guo E, Shi-hua YANG 2015, 29(4): 408-416.  DOI: 10．3969/j．issn．1001G7216．2015．04．010 Abstract ( )   HTML ( )   PDF (970KB) ( )   Crop regional trial is an important part of the crop breeding, registering and extension for new varieties. AMMI models and GGE biplots are very effective in the date analysis of the crop regional trial, especially in the evaluation of yielding ability, stability and adaptation for the tested varieties, while GGE biplots have gain more popularity in recent years. This article introduced GGE biplots, and used a data set from 2012 trial group B of the early maturity for late season indica rice in Southern China Rice Regional Trials as an example to demonstrate its effectiveness in the evaluation of yielding ability, stability and adaptation for the tested varieties. The paper also discussed the points for attentions or precautions in the application of the GGE biplots.

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Changes in Growth and Development and Main Enzyme Activities in Midgut of Cnaphalocrocis medinalis Intermittently Treated With Low Amount of Bt Rice Leaves over Generations Zhi-hong WU, Ya-jun YANG, Hong-xing XU, Xu-song ZHENG, Jun-ce TIAN, Yan-hui LU, Zhong-xian LV 2015, 29(4): 417-423.  DOI: 10．3969/j．issn．1001G7216．2015．04．011 Abstract ( )   HTML ( )   PDF (631KB) ( )   The developmental indices and main enzyme activities in midgut of Cnaphalocrocis medinalis treated with low amount of Bt rice leaves of T2A-1 (harboring cry2A gene) for three generations (5 h for every generation) were investigated to understand the response of C. medinalis to Bt rice. Results showed that developmental duration of 3rd-5th instar C. medinalis fed on Bt rice leaves in the 1st generation were prolonged and the emergence rates of C. medinalis sharply decreased compared with the untreated C. medinalis. However, these two indices returned to the level of the untreated C. medinalis with the increasing generations. The mortalities of the 3rd-5th instar C. medinalis larvae and the weight of female pupa lowered, and the weight of male pupa did not differ from that of untreated C. medinalis. Furthermore, the mortality of the 3rd-5th instar C. medinalis larvae and weight of male and female pupa did not return to or remain the levels of the untreated C. medinalis as the treated generations increased. These indices for the treated 3rd generation C. medinalis were lower than those of untreated C. medinalis. The total proteinase activities in C. medinalis larvae midgut juice fed on Bt rice leaves were lower than those in untreated C. medinalis, but the total proteinase activities followed an increasing trend with the increasing generations, and the similar trend was observed in the chymotrypsin-like enzyme activity of C. medinalis. While the activities of trypsin in the treated C. medinalis were higher than that in untreated C. medinalis and increased as treated generations increased, and the similar trend was observed in the aminopeptidase activity of C. medinalis. These results indicated that C. medinalis has potential adaptive ability under exposure to low amount of Cry2A protein.

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Expression Profiling and Function Analyses of LHSC70 in Laodelphax striatellus Li-hua WANG, Dan SHAN, Ji-chao FANG 2015, 29(4): 424-430.  DOI: 10．3969/j．issn．1001G7216．2015．04．012 Abstract ( )   HTML ( )   PDF (1042KB) ( )   Laodelphax striatellus is an major pest on rice in China. It has strong adaptability to environments and was found in all rice growing areas of the country. As a molecular chaperone, HSP70 plays an important role in biological growth and response to stress. HSC70,characterized by constitutive expression, is one of the most important members of the HSP70 family. To explore the adaptation mechanisms of L. striatellus to environments, LHSC70 expression profiling and function were analyzed. The results showed the complete cDNA of LHSC70 is 1971 bp in length, which encodes a protein of 656 amino acids, with a molecular weight of 71.6 kD and theoretical isoelectric point of 5.46. LHSC70 contains three signature sequences of HSP70 family and carries a typical HSP70 family structural signature. The phylogenic tree showed it shares 99% homology with HSC70 of Nilaparvata lugens. The expression of LHSC70 was associated with larval instar. The expression level of LHSC70 was highest in female adults and was similar in male adults and larvae at various instars. The difference in the expression of the gene was not significant after 10, 16, 22, 26, 30, 34, 38 and 42℃ treatments. Downregulated expression level of LHSC70 due to RNAi significantly decreased the tolerance of the female to heat stress, while exerted a less influence on the oviposition. These results suggested that LHSC70 is a 70 kD heat shock cognate protein and is not induced by heat stress, but it contributes the constitutive resistance to heat without close relation to reproduction in L. striatellus.

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Progress in the Allelic Variation of Wx Gene and Its Application in Rice Breeding Ji-hui ZHU, Chang-quan ZHANG, Ming-hong GU, Qiao-quan LIU 2015, 29(4): 431-438.  DOI: 10．3969/j．issn．1001G7216．2015．04．013 Abstract ( )   HTML ( )   PDF (514KB) ( )   The amylose content in endosperm is considered as the most important determinant influencing rice cooking and eating quality, and is quite different among rice cultivars. The Waxy (Wx) gene, controlling the synthesis of amylose in endosperm, is the major locus affecting rice quality. Up to now, several important Wx alleles had been identified, including Wxa, Wxb, wx, Wxop, Wxin, Wxmq, Wxmp and Wxhp, which might be the main reason for the wide diversity of rice grain quality. We reviewed the main Wx alleles and their effects on rice quality, as well as their application in rice breeding. Finally, the research perspective focusing on rice Wx gene is also discussed.

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Research Advances in Thermo-sensitive Leaf Coloration Mutants in Rice Yan-xia LIU, Dong-zhi LIN, Yan-jun DONG 2015, 29(4): 439-446.  DOI: 10．3969/j．issn．1001G7216．2015．04．014 Abstract ( )   HTML ( )   PDF (452KB) ( )   Temperature is one of the factors affecting the growth and development of rice. The rice mutant whose leaf-color varied with temperature is refered to thermo-sensitive leaf coloration mutant. Understanding the mechanism of thermo-sensitive leaf coloration mutation is significant for promoting genetic improvement and high-yielding breeding in rice. We reviewed the recent research progresses about phenotypes, genetic mapping, cloning, molecular mechanism, breeding and utilization of thermo-sensitive leaf coloration mutants in rice.