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28 September 2015, Volume 22 Issue 5 Previous Issue    Next Issue
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K-Domain Splicing Factor OsMADS1 Regulates Open Hull Male Sterility in Rice Lian-ping Sun, Ying-xin Zhang, Pei-pei Zhang, Zheng-fu Yang, Xiao-deng Zhan, Xi-hong Shen, Zhen-hua Zhang, Xia Hu, Dan-dan Xuan, Wei-xun Wu, Zi-he Li, Li-yong Cao, Shi-hua Cheng 2015, 22(5): 207-216.  DOI: 10.1016/S1672-6308(14)60303-6 Abstract ( )   HTML ( )   PDF (1110KB) ( )   We identified the rice floral organ development mutant, termed as open hull and male sterile 1 (ohms1), from the progeny of the indica restorer line Zhonghui 8015 treated with 60Co γ-ray irradiation. The ohms1 mutant exhibited an open hull and lemma- and palea-like structure conversion between the anthers and stigma, which resulted in the ohms1 mutant spikelet showing ‘tridentate lemma’. The ohms1 mutant was entirely sterile but had 60%-70% fertile pollen. Genetic analysis and gene mapping showed that ohms1 was controlled by a single recessive gene, and the mutant gene was fine-mapped to a 42-kb interval on the short arm of chromosome 3 between markers KY2 and KY29. Sequence analysis of the four open reading frames in this region revealed that the mutant carried a single nucleotide transformation (A to G) at the last base of the fifth intron, which was likely corresponded to ohms1 phynotype, in an MIKC type MADS-box gene OsMADS1 (LOC_Os03g11614). Enzyme digestion and cDNA sequencing further indicated that the variable splicing was responsible for the deletion of the sixth exon in ohms1, but no structural changes in the MADS domain or amino acid frame shifts appeared. Additionally, real-time fluorescent quantitative PCR analysis showed that the OsMADS1 expression level decreased significantly in the ohms1 mutant. The expression levels of rice flowering factors and floral glume development-related genes also changed significantly. These results demonstrate that OsMADS1 may play an important role in rice floral organ development, particularly in floral glume development and floret primordium differentiation.

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Genome-Wide Association Studies Reveal New Genetic Targets for Five Panicle Traits of International Rice Varieties Ya-fang Zhang, Yu-yin Ma, Zong-xiang Chen, Jie Zou, Tian-xiao Chen, Qian-qian Li, Xue-biao Pan, Shi-min Zuo 2015, 22(5): 217-226.  DOI: 10.1016/S1672-6308(14)60302-4 Abstract ( )   HTML ( )   PDF (987KB) ( )   Narrow genetic background is a key limiting factor in breeding stable high-yielding rice. The introduction and utilization of international rice core germplasm is an important way to increase the genetic diversity of domestic rice varieties. We conducted a genome-wide association study on 5 panicle traits of 315 rice accessions introduced from the international rice micro-core germplasm bank. Based on the tests from Yangzhou of China and Arkansas of American, environment exhibited a significant impacts on panicle length and primary branch number, while grain length, grain width and grain length/width ratio were insensitive to environment changes. We discovered a total of 7, 5, 10, 8 and 6 chromosomal regions or single nucleotide polymorphism marker loci that were significantly associated with primary branch number, panicle length, grain length, grain width and grain length/width ratio, respectively. Among them, eleven regions were associated with grain shape and one region associated with primary branch number, showing the good consistence in two different environments. Significant linear correlation was discovered between the average trait value and the number of favorable alleles carried by the varieties in all associated loci. Among the associated loci, varieties in aromatic and tropical japonica sub-groups possessed most favorable alleles, while those in temperate japonica sub-group contained the least. The domestic varieties mainly harbored unfavorable alleles in six of the associated loci being detected. On the contrary, 15 varieties from 11 different countries harbored more favorable alleles (as many as 30 or more) than the others. Remarkably, all these 15 varieties belonged to the tropical japonica sub-group. In conclusion, our study demonstrates that varieties in the tropical japonica sub-group had high potentials for breeding stable high-yielding rice. Based on this discovery, we proposed a new approach for improving the panicle traits of domestic rice by using tropical japonica varieties.

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Soaking Induced Changes in Chemical Composition, Glycemic Index and Starch Characteristics of Basmati Rice J. Kale S., K. Jha S., K. Jha G., P. Sinha J., B. Lal S. 2015, 22(5): 227-236.  DOI: 10.1016/S1672-6308(14)60296-1 Abstract ( )   HTML ( )   PDF (506KB) ( )   An attempt was made to determine the qualitative changes in basmati rice (Pusa Basmati 1121, PB1121) during soaking at 40 °C to 80 °C. Soaking temperature had significant effect (α = 0.01) on chemical composition, glycemic index and starch characteristics of rice. Starch content, apparent amylose content, crude protein content and crude fat content in un-soaked rice were found to be 73.24%, 27.26%, 8.79% and 2.56%, respectively, but differences in these traits were observed after soaking. Amylose to amylopectin ratio (Am/Ap) decreased from 0.59 to 0.52 (soaked at 80 °C). Crude fibre and crude ash contents increased after soaking. The mineral composition (K, P, S, Ca, Mg, Mn, Fe, Cu and Zn) in soaked rice was found to be 16.46% higher than un-soaked rice at the same degree of polishing. Glycemic index of un-soaked rice was found to be 58.41, but decreased to 54.31 after soaking at 80 °C. Pasting properties, scanning electron microscope images, and X-ray diffractograms suggested partial gelatinization of starch in the temperature range of 60 °C to 80 °C. Based on qualitative changes in rice (apparent amylose content, Am/Ap ratio and crystallinity rate), it was concluded that intermediate soaking temperatures (60 °C to 70 °C) would be useful for soaking of PB1121.

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Physiological Age Status of Female Adults and Off-Season Survival of Rice Leaffolder Cnaphalocrocis medinalis in India Chintalapati Padmavathi, Gururaj Katti, Vallabuni Sailaja, Yenumulag Prasad 2015, 22(5): 237-244.  DOI: 10.1016/S1672-6308(14)60304-8 Abstract ( )   HTML ( )   PDF (489KB) ( )   Rice leaffolder, Cnaphalocrocis medinalis, is one of the major foliage feeders found in the rice growing regions in India. When the crop was at maturity, numerous adults of rice leaffolder were found in the rice fields though the larval population gradually decreased, and no eggs were found on rice leaves. The population characteristics of C. medinalis were assessed based on the physiological age status of adults at different crop growth stages. Based on egg development within ovarioles, ovariole appearance, number and colour of fat bodies, and characteristics of bursa copulatrix, physiological age status of the adults was described, which served as a basis for the determination of age composition. C. medinalis adults were found during the first week of August on rice plants, of which 44% were in Age 0 with immature ovaries, indicating immigrants. However, 28% adults each were at Ages 1-2 with developing ovaries, indicating local breeding population. The carryover and off-season survival of C. medinalis were also studied to determine the contribution of the alternative hosts in the population growth that helped in devising efficient management strategies. Rice was the most preferred host followed by Triticum aestivum, Echinochloa crusgulli and Brachiaria plantaginea. Various routes of the carryover of C. medinalis from season to season were discussed.

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Discrimination of Transgenic Rice Based on Near Infrared Reflectance Spectroscopy and Partial Least Squares Regression Discriminant Analysis Long Zhang, Shan-shan Wang, Yan-fei Ding, Jia-rong Pan, Cheng Zhu 2015, 22(5): 245-249.  DOI: 10.1016/S1672-6308(14)60291-2 Abstract ( )   HTML ( )   PDF (443KB) ( )   Near infrared reflectance spectroscopy (NIRS), a non-destructive measurement technique, was combined with partial least squares regression discrimiant analysis (PLS-DA) to discriminate the transgenic (TCTP and mi166) and wild type (Zhonghua 11) rice. Furthermore, rice lines transformed with protein gene (OsTCTP) and regulation gene (Osmi166) were also discriminated by the NIRS method. The performances of PLS-DA in spectral ranges of 4 000-8 000 cm-1 and 4 000-10 000 cm-1 were compared to obtain the optimal spectral range. As a result, the transgenic and wild type rice were distinguished from each other in the range of 4 000-10 000 cm-1, and the correct classification rate was 100.0% in the validation test. The transgenic rice TCTP and mi166 were also distinguished from each other in the range of 4 000-10 000 cm-1, and the correct classification rate was also 100.0%. In conclusion, NIRS combined with PLS-DA can be used for the discrimination of transgenic rice.

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Characterization of Nitrogen Uptake Pattern in Malaysian Rice MR219 at Different Growth Stages Using 15N Isotope Mu’az Hashim Mohammad, Khanif Yusop Mohd, Othman Radziah, Abdul Wahid Samsuri 2015, 22(5): 250-254.  DOI: 10.1016/S1672-6308(14)60305-X Abstract ( )   HTML ( )   PDF (365KB) ( )   Nitrogen (N) use efficiency is usually less than 50%, and it remains a major problem in rice cultivation. Controlled release fertilizer (CRF) technology is one of the well-known efforts to overcome this problem. The efficiency of CRF, however, is very much dependent on the timing of nutrient release. This study was conducted to determine the precise time of N uptake by rice as a guideline to develop efficient CRF. Fertilizer N uptake by rice at different growth stages was investigated by using 15N isotopic technique. Rice was planted in pots, with 15N urea as N source at the rate of 120 kg/hm2. Potassium and phosphorus were applied at the same rate of 50 kg/hm2. Standard agronomic practices were employed throughout the growing periods. Rice plants were harvested every two weeks until maturation at the 14th week and analyzed for total N and 15N content. Nitrogen derived from fertilizer was calculated. Total N uptake in plants consistently increased until the 11th week. After that, it started to plateau and finally declined. Moreover, N utilization by rice plants peaked at 50%, which occurred during the 11th week after transplanting. N derived from fertilizer in rice plants were in the range of 18.7% to 40.0% in all plant tissues. The remaining N was derived from soil. Based on this study, N release from CRF should complete by the 11th week after planting to ensure the maximum fertilizer N uptake by rice plants. Efficient CRF should contribute to higher N derived from fertilizer which also resulted in a higher total N uptake by rice plants, increasing the potential of rice to produce higher yield while at the same time of reducing loss.