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28 May 2019, Volume 26 Issue 3 Previous Issue    Next Issue
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Review

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Agrobacterium-Mediated Transformation of Rice: Constraints and Possible Solutions Mohammed Sulaiman, Abd Samad Azman, Rahmat Zaidah 2019, 26(3): 133-146.  DOI: 10.1016/j.rsci.2019.04.001 Abstract ( )   HTML ( )   PDF (1069KB) ( )   Genetic transformation of rice (Oryza sativa L.) by introducing beneficial traits is now a central research instrument in plant physiology and a practical tool for plant improvement. Many approaches are verified for stable introduction of foreign genes into the plant genome. The review examined the different constraints that limit the success of rice genetic transformation via Agrobacterium-mediated approach and suggested possible solutions. Explant identification, gene transfer technique and construct to tailor the integration, transgene expression without collateral to genetic damage and transformant selection are among the technical challenges affecting the rice transformation. Despite the contests, Agrobacterium- mediated transformation system has been a better option for producing transgenic rice varieties because of its exact T-DNA processing and simple integration of low copy-number transgene. This information is necessary for improving the transformation system for recalcitrant rice varieties.

Research Papers

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Molecular Markers and Candidate Genes for Thermo-Sensitive Genic Male Sterile in Rice Khlaimongkhon Sudthana, Chakhonkaen Sriprapai, Pitngam Keasinee, Ditthab Khanittha, Sangarwut Numphet, Panyawut Natjaree, Wasinanon Thiwawan, Mongkolsiriwatana Chareerat, Chunwongse Julapark, Muangprom Amorntip 2019, 26(3): 147-156.  DOI: 10.1016/j.rsci.2018.08.006 Abstract ( )   HTML ( )   PDF (847KB) ( )   The discovery of thermo-sensitive genic male sterility (TGMS) has led to development of a simple and highly efficient two-line breeding system. In this study, genetic analysis was conducted using three F2 populations derived from crosses between IR68301S, an indica TGMS rice line, and IR14632 (tropical japonica), Supanburi 91062 (indica) and IR67966-188-2-2-1 (tropical japonica), respectively. Approximately 1:3 ratio between sterile and normal pollen of F2 plants from the three populations revealed that TGMS is controlled by a single recessive gene. Bulked segregant analysis using simple sequence repeat (SSR) and insertion-deletion (InDel) markers were used to identify markers linked to the tms gene. The linkage analysis based on the three populations indicated that the tms locus was located on chromosome 2 covering the same area. Using IR68301S × IR14632 F2 population, the results showed that the tms locus was located between SSR marker RM12676 and InDel marker 2gAP0050058. The genetic distance from the tms gene to these two flanking markers were 1.10 and 0.82 cM, respectively. InDel marker 2gAP004045 located between these two markers showed complete co-segregation with the TGMS phenotype. In addition, InDel marker vf0206114052 showed 2.94 cM linked to the tms gene using F2 populations of IR68301S × Supanburi 91062. These markers are useful tool for developing new TGMS lines by marker-assisted selection. There were ten genes located between the two flanking markers RM12676 and 2gAP0050058. Using quantitative real-time PCR for expression analysis, 7 of the 10 genes showed expression in panicles, and response to temperatures. These genes could be the candidate gene controlling TGMS in IR68301S.

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Comparative Efficacies of Next-Generation Insecticides Against Yellow Stem Borer and Their Effects on Natural Enemies in Rice Ecosystem Matiar Rahaman Muhammad, Joseph Stout Michael 2019, 26(3): 157-166.  DOI: 10.1016/j.rsci.2019.04.002 Abstract ( )   HTML ( )   PDF (672KB) ( )   The efficacies of some next-generation insecticides against the rice yellow stem borer (YSB), Scirpophaga incertulas (Walk.), and their compatibilities with natural enemies were investigated during 2014 and 2015. Three newer insecticides, chlorantraniliprole 0.4% G, dinotefuran 20% SG, and methoxyfenozide 24% SC, and two commonly used insecticides, carbufuran 5 G and quinalphos 25 EC, were evaluated in the field for their efficacies against YSB and their non-target effects on natural enemies. Application of chlorantraniliprole 0.4% G at 10.96 kg/hm2 resulted in the greatest reduction in YSB infestation (deadhearts and whiteheads) and greatest increase of yield compared to the untreated control plots, followed by methoxyfenozide 24% SC at 0.41 L/hm2, dinotefuran 20% SG at 0.15 kg/hm2, carbufuran 5 G at 10.96 kg/hm2, and quinalphos 25 EC at 1.50 L/hm2. All the insecticides reduced the numbers of predators viz., lady bird beetles, wolf spiders, carabid beetles, earwigs, green mirid bugs, and damselflies. Numbers of adults of the egg parasitoids Trichogramma sp., Telenomus sp. and Tetrastichus sp. were significantly reduced in insecticide-treated plots compared to untreated control plots. In all field trials, the harmful effects of the five insecticides were in the following rank order (least harmful to most harmful): chlorantraniliprole 0.4% G, carbufuran 5 G, dinotefuran 20% SG, methoxyfenozide 24% SC, and quinalphos 25 EC. On the basis of reduction in YSB infestation, increase in grain yield, and compatibility with natural enemies, chlorantraniliprole 0.4% G was proved to be the best of all the insecticides for YSB management system, although the study suggested minimizing its retail price for enhancement of cost effectiveness in farmers’ fields.

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Morpho-Physiological Changes in Roots of Rice Seedling upon Submergence T. Bui Liem, S. Ella Evangelina, L. Dionisio-Sese Maribel, M. Ismail Abdelbagi 2019, 26(3): 167-177.  DOI: 10.1016/j.rsci.2019.04.003 Abstract ( )   HTML ( )   PDF (718KB) ( )   Submergence is a serious environmental condition that causes large loss in rice production in rain fed lowland and flood affected area. This study evaluated morphological and physiological responses of rice roots to submergence using two tolerant rice genotypes FR13A and Swarna-Sub 1 and two sensitive ones Swarna and IR42. The tolerant genotypes had higher survival rate and less shoot elongation but greater root elongation during submergence than the sensitive ones. After submergence, the tolerant genotypes also had higher root dry weight and more active roots than the sensitive ones. Tolerant genotypes exhibited less root injury, with less malondialdehyde production and slower electrolyte leakage after submergence. Tolerant genotypes also maintained higher concentrations of soluble sugar and starch in roots and shoots and higher chlorophyll retention after submergence than the sensitive ones. Our data showed that root traits such as root activity and root growth are associated with survival rate after submergence. This is probably accomplished through higher energy supply, and membrane integrity is necessary to preserve root function and reduce injury during submergence. These root traits are important for submergence tolerance in rice.

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Morphological and Molecular Characterization of Novel Salt-Tolerant Rice Germplasms from the Philippines and Bangladesh F. Aala Jr Wilson, B. Gregorio Glenn 2019, 26(3): 178-188.  DOI: 10.1016/j.rsci.2018.09.001 Abstract ( )   HTML ( )   PDF (957KB) ( )   To screen for new sources of salinity tolerance, 688 traditional rice varieties from the Philippines and Bangladesh were obtained, and their tolerance to hypersaline conditions at the seedling stage was examined. A total of 29 Philippine lines and 15 Bangladeshi lines were scored as salt-tolerant. Morphological assessment (plant height, biomass and Na-K ratio) revealed that among the 44 salt-tolerant accessions, Casibon, Kalagnon and Ikogan had significantly higher relative shoot length difference, relative shoot growth reduction and shoot Na-K ratio than the tolerant check FL478. Additionally, AC and Akundo exhibited significantly higher Na-K ratios than the other genotypes. The genetic diversity of the 44 genotypes was assessed using 34 simple sequence repeat markers. A total of 133 alleles were detected across all loci. Cluster analysis showed that AC, Akundo and Kuplod were clustered along with FL478, indicating a strong genetic relatedness between these genotypes. IR29 (susceptible check) was singly separated. The haplotype analysis revealed that none of the 44 genotypes had a similar allele combination as FL478. These accessions are of interest since each genotype might be different from the classical salinity-tolerant Pokkali.

Short Communications

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Biochemical and Metabolomics on Rice Cultivars Puttaswamaiah Ranjitha Hurugalavadi, Gowda Rame, Nethra Nagarajappa, Amruta Narayanappa, Kumar Kandikattu Hemanth 2019, 26(3): 189-194.  DOI: 10.1016/j.rsci.2018.08.007 Abstract ( )   HTML ( )   PDF (940KB) ( )   Plant metabolites are important for both plant life and human nutrition. However, the genetic control of plant metabolome remains largely unknown. Here, we performed a genetic analysis of the different rice metabolome and isozymes which are highly versatile and non-destructive as bio-markers. Five isozymes peroxidase, catalase, malate dehydrogenase, alcohol dehydrogenase (ADH), polyphenol oxidase were studied to characterize the thirty rice cultivars and two hybrids KRH-2 and KRH-4 along with their parental lines. Among the zymograms, ADH was found to be useful for the detection of cultivars, like CTH1, IR64, IR30864, with an Rm value of 0.549. The metabolomics of rice cultivars by using gas chromatography coupled with mass spectrometry instrument with selected reaction monitoring mode software identified the 66 metabolites in the rice samples, including amino, organic, fatty acids, alcohols and sugars (mono-/dis-accharides). All metabolites investigated varied significantly among rice samples. Jaya had the higher number of metabolites (15) with a peak for each metabolite, followed by Jyothi (13). This study demonstrated a powerful tool and provided a high-quality data for understanding the plant metabolome and isozymes, which may help bridge the gap between the genome and phenome.

Letters

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Classification and Identification of indica P/TGMS Lines in China Mengchen Zhang, Shan Wang, Jianfang Yan, Shuiyong Sun, Xin Xu, Qun Xu, Xiaoping Yuan, Xinghua Wei, Yaolong Yang 2019, 26(3): 195-198.  DOI: 10.1016/j.rsci.2019.01.003 Abstract ( )   HTML ( )   PDF (557KB) ( )   SUMMARY Despite extensive studies on cultivated rice, the population structure and genetic diversity of the indica photoperiod- and thermo-sensitive genic male sterility (P/TGMS) lines in China remains unclear. Using 48 simple sequence repeat (SSR) markers, we genotyped a panel of 208 indica P/TGMS lines and confirmed three subgroups, named indica-I, indica-II and indica-III, in indica P/TGMS lines. Further diversity analysis indicated indica-II had the highest genetic diversity. The genetic differentiation between indica-II and indica-III was demonstrated as the largest among the three subgroups. Moreover, indica/japonica component identification was detected that five P/TGMS lines possess indica components less than 0.900. These results improve our knowledge on the genetic background for P/TGMS lines in China and will be beneficial for hybrid rice breeding programs.