scholarly journals Improved bacterial leaf blight disease resistance in the major elite Vietnamese rice cultivar TBR225 via editing of the OsSWEET14 promoter

PLoS ONE ◽  
2021 ◽  
Vol 16 (9) ◽  
pp. e0255470
Author(s):  
Phuong Nguyen Duy ◽  
Dai Tran Lan ◽  
Hang Pham Thu ◽  
Huong Phung Thi Thu ◽  
Ha Nguyen Thanh ◽  
...  

TBR225 is one of the most popular commercial rice varieties in Northern Vietnam. However, this variety is highly susceptible to bacterial leaf blight (BLB), a disease caused by Xanthomonas oryzae pv. oryzae (Xoo) which can lead to important yield losses. OsSWEET14 belongs to the SWEET gene family that encodes sugar transporters. Together with other Clade III members, it behaves as a susceptibility (S) gene whose induction by Asian Xoo Transcription-Activator-Like Effectors (TALEs) is absolutely necessary for disease. In this study, we sought to introduce BLB resistance in the TBR225 elite variety. First, two Vietnamese Xoo strains were shown to up-regulate OsSWEET14 upon TBR225 infection. To investigate if this induction is connected with disease susceptibility, nine TBR225 mutant lines with mutations in the AvrXa7, PthXo3 or TalF TALEs DNA target sequences of the OsSWEET14 promoter were obtained using the CRISPR/Cas9 editing system. Genotyping analysis of T0 and T1 individuals showed that mutations were stably inherited. None of the examined agronomic traits of three transgene-free T2 edited lines were significantly different from those of wild-type TBR225. Importantly, one of these T2 lines, harboring the largest homozygous 6-bp deletion, displayed decreased OsSWEET14 expression as well as a significantly reduced susceptibility to a Vietnamese Xoo strains and complete resistance to another one. Our findings indicate that CRISPR/Cas9 editing conferred an improved BLB resistance to a Vietnamese commercial elite rice variety.

2021 ◽  
Vol 43 (1) ◽  
Author(s):  
Vu Hoai Sam ◽  
Pham Thi Van ◽  
Nguyen Thanh Ha ◽  
Nguyen Thi Thu Ha ◽  
Phung Thi Thu Huong ◽  
...  

Bac thom 7 rice (BT7 rice) is one of the major elite rice cultivars in Vietnam with superior productivity and quality but very susceptible to bacterial leaf blight caused by Xanthomonas oryzae pv. oryzae. The gene OsSWEET14, belonging to the OsSWEET family which encodes sugar transport proteins, is considered to be a susceptible gene involved in the virulence of Xoo. At least three cis-elements (EBE - Effector-binding element), including Tal5, PthXo3 and AvrXa7 on BT7 OsSWEET14 promoter, bind specifically to well-known transcription activator–like effectors (TALEs) of many Asian Xoo bacterium strains. In this study, a T-DNA construct which expressed the protein-RNA complex CRISPR/Cas for editing three EBEs position on the OsSWEET14 promoter was designed. The recombinant binary vector was tested by PCR, restriction enzyme and finally sequencing and then successfully transferred to Bac thom 7 rice through Agrobacterium tumefaciens. 28 of 30 hygromycin-resistant regenerated rice lines that grew and developed normally under nethouse conditions were selected by PCR with specific primers. Among these, twelve transgenic rice lines were identified carrying one copy of the T-DNA construct. The presence of CRISPR/Cas9-induced mutations of the targeted promoter in the transgenic plants were confirmed by T7EI assay. These results provide the basis to determine the role of OsSWEET14 in the susceptibility of Bac thom 7 rice to Xanthomonas oryzae pv. oryzae -caused disease, towards the further goal of generating an improved Bac thom 7 rice variety with broad-spectrum bacterial leaf blight resistance using CRISPR/Cas9 technology. 


2020 ◽  
Vol 20 (2) ◽  
pp. 43
Author(s):  
Nafisah Nafisah ◽  
Celvia Roza ◽  
Nani Yunani ◽  
Aris Hairmansis ◽  
Tita Rostiati ◽  
...  

<p class="abstrakinggris">Hundred of high yielding and bacterial leaf blight (<em>Xanthomonas oryzae</em> pv. <em>oryzae, Xoo</em>) resistant rice varieties released since the 1960s are important sources of genetic materials for exploring superior genotypes. The study aimed to evaluate the genetic resistance of 177 rice varieties to <em>Xoo</em> and their agronomic traits. The evaluations were conducted at the Indonesian Center for Rice Research Experimental Station during the wet season (December 2015-March 2016). The bacterial leaf blight resistance was evaluated for <em>Xoo</em> pathotypes III, IV, and VIII using the clipping method. The genetic variation among genotypes was categorized as low (0–10%), medium (10–20%), and high (&gt;20%), whereas the heritability was categorized as low (0-30%), medium (30-60%), and high (&gt;60%). The variability of resistance to <em>Xoo</em> pathotypes, grain yield, and spikelet fertility was low, while the variability of plant height, productive tiller number, filled grain, and total spikelet was medium, and the variability of unfilled grain number was high. The 29 varieties  were categorized as superior based on their agronomic traits or resistance to <em>Xoo</em> pathotypes. In conclusion, Batutegi and Fatmawati were superior in the total spikelet number, while Rojolele and Inpari 2 were supreme in the thousand-grain weight. Dodokan had a very short maturity, and Inpari 24, Conde, Kalimas, Angke, Inpari 17, and Inpara 8 had the highest resistance to <em>Xoo</em> pathotypes. The study implies that the identified rice superior genotypes could be used as genetic materials to design cross combinations for higher yield potential and BLB resistance varietal improvement.</p>


2020 ◽  
Vol 39 (1) ◽  
pp. 11
Author(s):  
Fatimah Fatimah ◽  
Joko Prasetiyono

<p>Bacterial leaf blight (BLB) caused by Xanthomonas oryzae pv oryzae (Xoo) is an important bacterial disease and very destructive to rice plant. BLB decreased rice production from 20%-30% up to 80%. Host-plant resistance is a cost-effective and environmentally safe approach to reduce yield loss. However the development of new rice variety by conventional selection would take several years. The genetic improvement in rice production considered as a vital program in order to ensure national food security. The availability of corresponding molecular marker makes it more precision and efficient by reducing the time required for selection. This present article highlights the molecular approach in breeding for BLB disease resistant rice varieties. In detail, it will be discussed the application of molecular marker assisted backcrossing and pyramiding gene resistance offered breeders to accelerate the rice breeding program for resistance to BLB. The pyramiding of three resistance BLB genes (xa5, Xa7, and Xa21and one gene (Xa4) as a background into two elite indica rice varieties, Ciherang and Inpari 13, was introduced successfully. The combining of conventional breeding, marker assisted backcrossing, disease evaluation, agronomic performance and yield has led the significant resistance of pyramid lines to Xoo Race III, IV and VIII in vegetative and generative phase while their yield potential was maintained (6-7 ton/ha). The current status of Ciherang-HDB and Inpari 13-HDB pyramid lines is the production of nucleoseeds and breeder seeds. This broad spectrum and durable resistance characteristic may help in controlling BLB disease in different region of Indonesia and it will facilitate the rice self-sustainability program.</p><p>Keywords: Rice, gene pyramiding, plant breeding, molecular marker.</p><p> </p><p><strong>Abstrak</strong></p><p>Penyakit hawar daun bakteri (HDB) yang disebabkan oleh Xanthomonas oryzae pv oryzae (Xoo) merupakan penyakit penting pada tanaman padi karena dapat menurunkan produksi padi rata-rata 20-30% bahkan dapat mencapai 80%. Penggunaan varietas tahan merupakan cara pengendalian yang paling efektif, ramah lingkungan, dan mudah dilakukan. Namun pengembangan varietas unggul baru melalui seleksi konvensional memerlukan waktu lebih lama. Perbaikan varietas padi perlu terus dikembangkan dalam mendukung ketahanan pangan dan kemandirian pangan nasional. Tersedianya marka molekuler membantu proses pemuliaan tanaman menjadi lebih presisi dan lebih efisien sehingga mengurangi waktu seleksi pada tanaman progeni. Tulisan ini memfokuskan pendekatan molekuler dalam pemuliaan varietas tahan penyakit HDB melalui piramida gen ketahanan untuk mempercepat progam pemuliaan padi tahan penyakit HDB. Kegiatan menggabungkan tiga gen ketahanan (xa5, Xa7, dan Xa21) dan satu gen (Xa4) sebagai background ke dalam padi varietas Ciherang dan Inpari-13 telah berhasil dilakukan. Melalui penggabungan beberapa pendekatan yaitu pemuliaan konvensional dan silang balik berbantu marka, evaluasi penyakit dan keragaan agronomi serta komponen hasil telah menunjukkan peningkatan ketahanan yang nyata pada galur-galur piramida Ciherang HDB dan Inpari-13 HDB pada tiga ras Xoo (Ras III, IV, dan VIII), baik pada fase vegetatif maupun generatif dengan potensi hasil tidak berbeda nyata dengan tetuanya (6-7 t/ha). Saat ini sudah diproduksi benih inti (NS) dan benih penjenis (BS) galur-galur piramida Ciherang HDB dan Inpari-13 HDB. Dengan demikian, galur-galur piramida memiliki spektrum yang luas dan mampu bertahan dalam jangka waktu lama sehingga dapat mengontrol penyakit HDB di berbagai wilayah Indonesia dan mendukung target pemerintah untuk mempertahankan swasembada beras secara berkelanjutan.</p><p>Kata kunci: Padi, piramida gen, pemuliaan tanaman, marka molekuler.<br /><br /></p><p> </p>


2020 ◽  
Vol 23 (2) ◽  
pp. 87
Author(s):  
Fatimah Fatimah ◽  
Joko Prasetiyono ◽  
Ahmad Dadang ◽  
Tasliah Tasliah ◽  
Masumah Masumah

Heading date is one of key traits in rice adaptation to different environments. Rice with early maturity is very useful for increasing rice production extensively especially in Indonesia. The improvement of rice variety Conde for heading date and resistance to bacterial leaf blight (BLB) was developed through Marker Assisted Backcrossing approach (MAB). Xa7 derived from Conde as recipient parents for resistance to BLB and Hd2 gene derived from Nipponbare as a donor parent for heading date. The aim of this research was to evaluate the performance of heading date and agronomic traits of 85 BC2F4 lines in two field stations, Sukamandi (West Java) and Maros (South Sulawesi). Molecular analysis of Xa7 on chromosome 6 and Hd2 gene on chromosome 7 and agronomic performance was evaluated. Foreground analysis resulted 41% for Xa7 and 66.7% for Hd2 gene in homozygous condition. The majority of lines have similar heading date and yield with Conde and more resistance to bacterial leaf blight (BLB) than Conde. Six lines flowered earlier 5 days than Conde in Sukamandi and three lines flowered earlier 3 days in Maros. Twelve lines with flowered earlier than Conde, resistance to BLB and similar yield with Conde were selected for background analysis resulted 93% genome recovery. These lines would be further evaluated in preliminary yield trail for their stability.


2019 ◽  
Vol 23 (2) ◽  
pp. 205
Author(s):  
Tri Joko ◽  
Kristamtini Kristamtini ◽  
Sumarno Sumarno ◽  
Rofiq Andriyanto

Bacterial leaf blight (BLB) caused by Xanthomonas oryzae pv. oryzae (Xoo) is an important disease in rice plants worldwide, including in Indonesia. The use of resistant variety against BLB is the best effort in disease control because it is considered as the most effective and environmentally friendly. This study aimed to evaluate the resistance of local varieties, red rice (cv. Sembada Merah) and black rice (cv. Sembada Hitam), against Xoo compared to white rice variety (Ciherang), commonly cultivated by the farmers. The study was conducted in a greenhouse and arranged in Factorial of Completely Randomized Design (CRD) with 5 replications and 2 treatment factors: variety (Sembada Hitam, Sembada Merah, and Ciherang) and inoculation (with and without inoculated by Xoo bacterial suspension). Xoo inoculation was performed by clipping the leaves that close to the reproductive phase when the heading begins to be produced. The disease intensity and Area Under Disease Progress Curve (AUDPC) over two weeks were used to determine the level of resistance of the tested plant varieties. The results showed that black rice and red rice had better levels of resistance against BLB compared to white rice. At two weeks after inoculation, Sembada Hitam had the lowest AUDPC value followed by Sembada Merah, while the Ciherang had the highest AUDPC value and was categorized as a susceptible variety to Xoo.


2016 ◽  
Vol 44 (2) ◽  
pp. 126
Author(s):  
Ermelinda Maria Lopes Hornai ◽  
Bambang Sapta Purwoko ◽  
Willy Bayuardi Suwarno ◽  
Dan Iswari Saraswati Dewi

ABSTRACT<br /><br />Hybrid rice varieties  is an alternative technology to improve  productivity of low land rice. The results of previous studies have identified and found the male sterile lines Wild Abortive type and Kalinga are resistant to bacterial leaf blight pathotype III, IV and VIII. The objectives of the research were to obtain information on agronomic characters, yield evaluation, genetic parameters, and repeatability information. The experiment was conducted in two locations namely  Muara and Indramayu experimental stations. The design used was a Randomized Complete Block Design with three replication at each site.  Each replicate consisted of 17 hybrid rice and three check varieties. The results from locations showed that genotype BI485A/BP1 (IR53942) has the highest yield of 5.8 ton ha-1. The coefficient of genetic and phenotypic diversity of six agronomic characters was low. The repeatability for seven character observed were low, except for days to flowering. The  scoring value  of bacterial leaf blight disease in Indramayu showed that nine genotypes exhibit resistance.<br /><br />Keywords: cytoplasmic male sterile lines, disease resistance <br /><br />


2014 ◽  
Vol 2 (3) ◽  
pp. 229-237 ◽  
Author(s):  
Manu Maya Magar ◽  
Ch.V. Durga Rani ◽  
G Auradha

The present investigation was undertaken with the objective to develop high yielding, fine grain rice varieties possessing broad spectrum durable resistance by transferring bacterial leaf blight (BLB) resistant genes viz., xa13 and Xa21 from B95-1. A popular high yielding and fine grain rice variety, MTU1010 (Cottondora Sannalu), susceptible to BLB and B95-1 carrying resistant genes for BLB (xa13 & Xa21 genes) was selected as the parent for crossing. B95-1 was verified for the presence of target genes by using gene linked primers viz., xa13 promotor and pTA 248. These primers were also used to study polymorphism between resistant (B95-1) and susceptible (MTU1010) parents. The cross viz., MTU1010 x B95-1 was affected during Rabi, 2010 and F1 progenies were confirmed during Kharif, 2011. The F1 plants confirmed as true hybrids for both the genes were advanced to F2 generation and foreground selection was done using gene linked markers. Genetic analysis in F2 populations confirmed that the genes (xa13 & Xa21) governing BLB resistance followed Mendelian inheritance. The phenotypic data analysis revealed that the plants carrying two resistance gene combinations (xa13xa13 Xa21Xa21, xa13xa13Xa21xa21) showed BLB resistance (0-2 scale), while the gene combinations viz., Xa13Xa13Xa21Xa21, Xa13Xa13Xa21xa21, and Xa13xa13Xa21Xa21, Xa13xa13Xa21xa21 showed BLB resistance (0.5-3.0).DOI: http://dx.doi.org/10.3126/ijasbt.v2i3.10570 Int J Appl Sci Biotechnol, Vol. 2(3): 229-237   


2020 ◽  
Vol 110 (2) ◽  
pp. 267-277
Author(s):  
C. Tekete ◽  
S. Cunnac ◽  
H. Doucouré ◽  
M. Dembele ◽  
I. Keita ◽  
...  

Bacterial leaf blight caused by Xanthomonas oryzae pv. oryzae represents a severe threat to rice cultivation in Mali. Characterizing the pathotypic diversity of bacterial populations is key to the management of pathogen-resistant varieties. Forty-one X. oryzae pv. oryzae isolates were collected between 2010 and 2013 in the major rice growing regions in Mali. All isolates were virulent on the susceptible rice variety Azucena; evaluation of the isolates on 12 near isogenic rice lines, each carrying a single resistance gene, identified six new races (A4 to A9) and confirmed race A3 that was previously reported in Mali. Races A5 and A6, isolated in Office du Niger and Sélingué, were the most prevalent races in Mali. Race A9 was the most virulent, circumventing all of the resistance genes tested. Xa3 controlled six of seven races (i.e., 89% of the isolates tested). The expansion of race A9 represents a major risk to rice cultivation and highlights the urgent need to identify a local source of resistance. We selected 14 isolates of X. oryzae pv. oryzae representative of the most prevalent races to evaluate 29 rice varieties grown by farmers in Mali. Six isolates showed a high level of resistance to X. oryzae pv. oryzae and were then screened with a larger collection of isolates. Based on the interactions among the six varieties and the X. oryzae pv. oryzae isolates, we characterized eight different pathotypes (P1 to P8). Two rice varieties, SK20-28 and Gigante, effectively controlled all of the isolates tested. The low association observed among races and pathotypes of X. oryzae pv. oryzae suggests that the resistance observed in the local rice varieties does not simply rely on single known Xa genes. X. oryzae pv. oryzae is pathogenically and geographically diverse. Both the races of X. oryzae pv. oryzae characterized in this study and the identification of sources of resistance in local rice varieties provide useful information to inform the design of effective breeding programs for resistance to bacterial leaf blight in Mali.


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