Introgression of bacterial leaf blight (BLB) resistant gene, Xa7 into MARDI elite variety, MR219 by marker assisted backcrossing (MABC) approach

Bacterial leaf blight (BLB) is one of the major rice diseases in Malaysia. This disease causes substantial yield loss as high as 70%. Development of rice varieties which inherited BLB resistant traits is a crucial approach to promote and sustain rice industry in Malaysia. Hence, this study aims were to enhance BLB disease resistant characters of high yielding commercial variety MR219 through backcross breeding approach with supporting tool of marker-assisted selection (MAS). Broad spectrum BLB resistance gene, Xa7 from donor parent IRBB7 were introgressed into the susceptible MR219 (recurrent parent) using two flanking markers ID7 and ID15. At BC3F4, we managed to generate 19 introgressed lines with homozygous Xa7 gene and showed resistant characteristics as donor parent when it was challenged with Xanthomonas oryzae pv. oryzae through artificial inoculation. Recurrent parent MR219 and control variety, MR263 were found to be severely infected by the disease. The improved lines exhibited similar morphological and yield performance characters as to the elite variety, MR219. Two lines, PB-2-107 and PB-2-34 were chosen to be potential lines because of their outstanding performances compared to parent, MR219. This study demonstrates a success story of MAS application in development of improved disease resistance lines of rice against BLB disease.

Phenotypic Evaluation of Advanced Breeding Lines for Resistance against Bacterial Leaf Blight Disease in Rice (Oryza sativa L.)

Bacterial Leaf Blight disease epidemically damaged the rice crop. Absence of resistance against BLB disease in MTU1010 is one of the main reason for these epidemics. Thus, there is urgent need to search for resistant source and subsequently, their phenotypic evaluation to validate the resistant source. In this paper discussing about the highlights of phenotypic evaluation of Bacterial Leaf Blight resistance in MTU1010 NIL variety of rice. In the present study, fifty advanced breeding lines along with parents i.e., MTU1010 NIL X Akshayadhan NIL, were screened for bacterial leaf blight disease, Thirty-four breeding lines were shown resistance against bacterial leaf blight disease.

Phenotypic Screening of F4 Breeding Lines against Bacterial Blight Disease in Rice

Biotic stresses are major threat to rice production. Among biotic stresses, bacterial leaf blight is one of the major diseases affecting rice grain production in rice growing areas. Present investigation was conducted to evaluate phenotypic effect of 50 breeding lines from a cross (Pranahitha//ISM/MTU1010) in glass house at Regional Agricultural Research Station, Jagtial by inoculating Bacterial leaf blight culture (DX-020) by leaf clipping method. Out of these 50 F4 lines evaluated, twenty nine breeding lines showed resistant reaction with disease score of 1. Eleven lines showed moderately resistant reaction with disease score 3. Twenty nine breeding lines that were resistant with disease score 1, had excellent grain yield. Hence, these lines can be advanced to further generations. Thus the present study has demonstrated that phenotypic selection is successful in the glass house and these breeding lines with higher yield levels are expected to perform better in the field trials and further in the farmers fields with the good level of bacterial blight resistance.

Development of New Rice (Oryza. sativa L.) Breeding Lines through Marker-Assisted Introgression and Pyramiding of Brown Planthopper, Blast, Bacterial Leaf Blight Resistance, and Aroma Genes

Brown planthopper, blast, and bacterial blight are the main biotic stressors of rice and can cause a massive loss in rice production. Aroma is an important character of rice quality. It is of far-reaching significance to breed resistant and high-quality varieties using germplasms with objective genes. In this study, the introgression and pyramiding of brown planthopper (BPH), blast, and bacterial leaf blight (BLB) resistance genes and aroma genes into elite rice maintainers and restorers were conducted through conventional cross-breeding coupled with the marker-assisted selection (MAS) breeding method. Single-plant selection was performed from F2 onwards to select desirable recombinants possessing alleles of interest with suitable phenotypes. Respective linked markers were used in each generation from intercrossing to the F7 generation for tracking the presence of targeted genes. A total of 74 improved lines (ILs) have been developed which possess a combination of 1 to 4 genes for BPH, blast, and BLB resistance and aroma. These ILs showed moderate to high resistance to multiple biotic stresses (BPH, blast and BLB) or aromatic fragrance without obvious negative effects on agronomic traits. As multiple resistance and aromatic traits have become significant objectives in rice breeding, these resistance and/or aroma gene introgressed or pyramided lines have important application prospects. Core ideas: (1) marker-assisted breeding was used to pyramid multiple genes for an elite breeding line; (2) improved lines with the introgression of 1–4 genes were developed to achieve high resistance against various biotic stresses and aroma; (3) new lines were used as donor parents to introgress multiple genes in other genetic backgrounds.

Discovery of Novel Dihydrolipoamide S-Succinyltransferase Inhibitors Based on Fragment Virtual Screening

A series of new oxadiazole sulfone derivatives containing an amide moiety was synthesized based on fragment virtual screening to screen high-efficiency antibacterial agents for rice bacterial diseases. All target compounds showed greater bactericidal activity than commercial bactericides. 3-(4-fluorophenyl)-N-((5-(methylsulfonyl)-1,3,4-oxadiazol-2-yl)methyl)acrylamide (10) showed excellent antibacterial activity against Xanthomonas oryzae pv. oryzae and Xanthomonas oryzae pv. oryzicola, with EC50 values of 0.36 and 0.53 mg/L, respectively, which were superior to thiodiazole copper (113.38 and 131.54 mg/L) and bismerthiazol (83.07 and 105.90 mg/L). The protective activity of compound 10 against rice bacterial leaf blight and rice bacterial leaf streak was 43.2% and 53.6%, respectively, which was superior to that of JHXJZ (34.1% and 26.4%) and thiodiazole copper (33.0% and 30.2%). The curative activity of compound 10 against rice bacterial leaf blight and rice bacterial leaf streak was 44.5% and 51.7%, respectively, which was superior to that of JHXJZ (32.6% and 24.4%) and thiodiazole copper (27.1% and 28.6%). Moreover, compound 10 might inhibit the growth of Xanthomonas oryzae pv. oryzae and Xanthomonas oryzae pv. oryzicola by affecting the extracellular polysaccharides, destroying cell membranes, and inhibiting the enzyme activity of dihydrolipoamide S-succinyltransferase.

Penggunaan Pestisida Biorasional untuk Pengendalian Penyakit Hawar Daun Bakteri pada Tanaman Padi

Bacterial leaf blight can cause rice loss between 15-80%. Biorational pesticides can be an alternative to controlling the disease. Bacillus firmus, Burkholderia sp, and Serratia marcescens against bacterial leaf blight on rice plants in the field. The study was conducted in Maret-Juni 2014 in the land of the Independent Farmers Group, Cipeuyeum Village, Haurwangi District, Cianjur Regency, West Java. The design uses a randomized complete block design (RCBD) with 6 treatments and 4 replications. The treatments consist of: 1) Mekongga + biorational, 2) Inpari 14 + biorational, 3) Sintanur + biorasional, 4) Mekongga + without biorational, 5) Inpari 14 + without biorational, and 6) Sintanur + without biorational. The results of the study showed that the application of biorational pesticides can reduce the intensity of bacterial leaf blight disease. Sintanur varieties with the application of biorational pesticides produce higher and higher R / C ratios of 6.81 tons ha-1 and 2.79.

Response of a local rice variety Pandanwangi to infection of bacterial leaf blight Xanthomonas oryzae pv. oryzae strain III, IV, and VIII

Bacterial leaf blight (BLB) caused by Xanthomonas oryzae pv. oryzae (Xoo) is one of the limiting factors in rice production. A local cultivar, rice “Pandanwangi” is a superior variety much preferred and cultivated by the farmers in Cianjur, West Java, Indonesia. The information about the response of “Pandangwangi” to Xoo is still poorly understood. This paper reports the results of the evaluation of “Pandanwangi” response against BLB. This research was conducted in a greenhouse with artificial inoculation using Xoo strains III, IV, and VIII with bacterial suspension at 108 cfu.mL−1. The results showed that the response of cv Pandanwangi to Xoo infection was different from the strain of Xoo. “Pandanwangi” cultivar was susceptible to Xoo strain III and VIII and very susceptible to strain IV.