Improving rice production is of current global concern so that food security is maintained especially in developing nations where rice remains as the staple food. With the aid of molecular biology, various isolated genes conferring to abiotic, biotic and herbicide stress tolerance has been successfully transferred into rice. Attempts have also been made to enhance grain yield, nutritional characteristics, fragrance and photosynthetic capacity of rice. The success of a commercialized transgenic rice largely depends on the biosafety and environmental risks assessments as these information translates into consumers’ acceptance towards genetically modified (GM) rice. As the renowned Golden Rice has received the green light for field trial in the Philippines and Bangladesh, this would serve as a catalyst for better acceptance of GM food crops. A brief case study on the commercialization of transgenic BT rice in China will also be discussed. The review aims to bring useful insights for future endeavors in improving traits for rice through genetic engineering.
Crown rot caused by fungal pathogen is the most prevalent postharvest disease in banana fruit that results significant economic losses during transportation, storage, and ripening period. Antifungal effects of ultraviolet C (UVC) irradiation at doses varied from 0.01 to 0.30 kJ m-2 were investigated in controlling postharvest crown rot disease, maintenance of fruit quality, and the effects on antioxidant capacity of Berangan banana fruit during ripening days at 25 ± 2°C and 85% RH. Fruits irradiated with 0.30 kJ m-2 exhibited the highest (i.e., 62.51%) reduction in disease severity. However, the application of UVC at all doses caused significant browning damages on fruit peel except the dose of 0.01 kJ m-2. This dose synergistically reduced 46.25% development of postharvest crown and did not give adverse effects on respiration rate, ethylene production, weight loss, firmness, color changes, soluble solids concentration, titratable acidity, and pH in banana as compared to the other treatments and control. Meanwhile, the dose also enhanced a significant higher level of total phenolic content, FRAP, and DPPH values than in control fruits indicating the beneficial impact of UVC in fruit nutritional quality. The results of scanning electron micrographs confirmed that UVC irradiation retarded the losses of wall compartments, thereby maintained the cell wall integrity in the crown tissue of banana fruit. The results suggest that using 0.01 kJ m-2 UVC irradiation dose as postharvest physical treatment, the crown rot disease has potential to be controlled effectively together with maintaining quality and antioxidant of banana fruit.
A total of 325 bacteria were isolated from both healthy and sheath blight infected leaf samples of rice plants, collected from different places of Malaysia, following dilution technique. Sheath blight pathogen was isolated from infected samples by tissue plating method. Out of 325, 14 isolates were found to be antagonist against the pathogen in pre evaluation test. All the 14 isolates were morphologically characterized. Antagonistic activity of these isolates was further confirmed by adopting the standard dual culture and extracellular metabolite tests. The best isolates were selected, based on the results. In dual culture test, the selected bacterial isolates KMB25, TMB33, PMB38, UMB20 and BMB42 showed 68.44%, 60.89%, 60.22%, 50.00% and 48.22% fungal growth inhibition, respectively and in extracellular metabolite test these bacterial isolates exhibited 93.33%, 84.26%, 69.82%, 67.96% and 39.26% of the same, respectively. Biochemical tests of selected isolates were performed following standard procedure. These bacterial isolates were tentatively identified as fluorescent pseudomonas by morphological and biochemical characterization. The identities were further confirmed by Biolog microstation system as P. fluorescens (UMB20), P. aeruginosa (KMB25, TMB33 and PMB38) and P. asplenii (BMB42) with similarity index ranging from 0.517 to 0.697. The effective bacterial isolates obtained from the present study can be used in the management of soil borne fungal pathogen Rhizoctonia solani, causing sheath blight of rice.
A reverse transcription loop-mediated isothermal amplification (RT-LAMP) detected Coconut cadang-cadang viroid (CCCVd) within 60 min at 60 °C in total nucleic acid extracted from oil palm leaves infected with CCCVd. Positive reactions showed colour change from orange to green in the reaction mix after the addition of fluorescent reagent, and a laddering pattern band on 2% agarose gel electrophoresis. Conventional RT-PCR with LAMP primers produced amplicons with a sequence identical to the 297-nt CCCVd oil palm variant with the primers being specific for CCCVd and not for other viroids such as PSTVd and CEVd. RT-LAMP was found to be rapid and specific for detecting oil palm CCCVd.
Morphological features and Inter Simple Sequence Repeat (ISSR) polymorphism were employed to analyse 21 Corynespora cassiicola isolates obtained from a number of Hevea clones grown in rubber plantations in Malaysia. The C. cassiicola isolates used in this study were collected from several states in Malaysia from 1998 to 2005. The morphology of the isolates was characteristic of that previously described for C. cassiicola. Variations in colony and conidial morphology were observed not only among isolates but also within a single isolate with no inclination to either clonal or geographical origin of the isolates. ISSR analysis delineated the isolates into two distinct clusters. The dendrogram created from UPGMA analysis based on Nei and Li's coefficient (calculated from the binary matrix data of 106 amplified DNA bands generated from 8 ISSR primers) showed that cluster 1 encompasses 12 isolates from the states of Johor and Selangor (this cluster was further split into 2 sub clusters (1A, 1B), sub cluster 1B consists of a unique isolate, CKT05D); while cluster 2 comprises of 9 isolates that were obtained from the other states. Detached leaf assay performed on selected Hevea clones showed that the pathogenicity of representative isolates from cluster 1 (with the exception of CKT05D) resembled that of race 1; and isolates in cluster 2 showed pathogenicity similar to race 2 of the fungus that was previously identified in Malaysia. The isolate CKT05D from sub cluster 1B showed pathogenicity dissimilar to either race 1 or race 2.
Landscape-grown foxtail palm (Wodyetia bifurcata A. K. Irvine) trees displaying symptoms of severe foliar chlorosis, stunting, general decline and mortality reminiscent of coconut yellow decline disease were observed in Bangi, Malaysia, during 2012. DNA samples from foliage tissues of 15 symptomatic palms were analysed by employing a nested PCR assay primed by phytoplasma universal ribosomal RNA operon primer pairs, P1/P7 followed by R16F2n/R2. The assay yielded amplicons of a single band of 1.25 kb from DNA samples of 11 symptomatic palms. Results from cloning and sequence analysis of the PCR-amplified 16S rRNA gene segments revealed that, in three palms, three mutually distinct phytoplasmas comprising strains related to 'Candidatus Phytoplasma asteris' and 'Candidatus Phytoplasma cynodontis', as well as a novel phytoplasma, were present as triple infections. The 16S rRNA gene sequence derived from the novel phytoplasma shared less than 96 % nucleotide sequence identity with that of each previously describedspecies of the provisional genus 'Ca. Phytoplasma', justifying its recognition as the reference strain of a new taxon, 'Candidatus Phytoplasma wodyetiae'. Virtual RFLP profiles of the R16F2n/R2 portion of the 16S rRNA gene and the pattern similarity coefficient value (0.74) supported the delineation of 'Ca. Phytoplasma wodyetiae' as the sole representative subgroup A member of a new phytoplasma ribosomal group, 16SrXXXVI.