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You searched for subject:(Bru1). Showing records 1 – 2 of 2 total matches.

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Louisiana State University

1. Avellaneda Barbosa, Mavir Carolina. Screening for Resistance to Sugarcane Brown Rust with Controlled Conditions Inoculation.

Degree: MS, Plant Sciences, 2014, Louisiana State University

Brown rust, caused by Puccinia melanocephala, is an important disease of sugarcane. Breeding for host plant resistance is the primary control measure. Screening for resistance has relied on rating the severity of symptoms caused by natural infection; however, erratic results make this method problematic. A method accomplishing both infection and disease expression under controlled conditions could avoid the problems associated with resistance evaluations under natural infection. Inoculation of seedlings was evaluated to determine whether it could provide accurate resistance ratings in cross appraisal, and inoculation under controlled conditions was evaluated for the potential to accurately determine resistance reactions in clones with known and unknown reactions in comparison to field reactions. Seedlings from crosses between parents with different levels of resistance were inoculated with urediniospores at concentrations ranging from 1 x 103 to 1 x 106 spores per ml. Disease severity was visually assessed at 1 and 2 weeks after inoculation, and resistance ratings were assigned on a modified 1 to 9 scale. Inoculum concentration strongly affected severity and the frequency of resistant progeny in crosses. Brown rust resistance is a heritable trait; however, parental reaction was not a consistent determinant of progeny distribution across resistance rating categories. These results suggest that seedling inoculation may not be suitable for the evaluation of brown rust resistance. Clones were inoculated with 1 x106 spores per ml, and severity was determined as percentage of leaf area occupied by rust lesions by image analysis. Resistance reactions could not be reliably determined for susceptible clones in single inoculations. Controlled conditions inoculation and natural infection results were not correlated. Multiple inoculations under controlled conditions accurately identified resistant and susceptible clones with severe infection resulting from any single inoculation indicating susceptibility. Therefore, controlled conditions inoculation has the potential to be useful in limited studies to characterize parents in a recurrent selection program and for basic studies of resistance to brown rust.

Subjects/Keywords: Resistance; Bru1; Disease severity; Sugarcane; Brown rust

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Avellaneda Barbosa, M. C. (2014). Screening for Resistance to Sugarcane Brown Rust with Controlled Conditions Inoculation. (Masters Thesis). Louisiana State University. Retrieved from etd-07112014-170420 ; https://digitalcommons.lsu.edu/gradschool_theses/1426

Chicago Manual of Style (16th Edition):

Avellaneda Barbosa, Mavir Carolina. “Screening for Resistance to Sugarcane Brown Rust with Controlled Conditions Inoculation.” 2014. Masters Thesis, Louisiana State University. Accessed November 22, 2019. etd-07112014-170420 ; https://digitalcommons.lsu.edu/gradschool_theses/1426.

MLA Handbook (7th Edition):

Avellaneda Barbosa, Mavir Carolina. “Screening for Resistance to Sugarcane Brown Rust with Controlled Conditions Inoculation.” 2014. Web. 22 Nov 2019.

Vancouver:

Avellaneda Barbosa MC. Screening for Resistance to Sugarcane Brown Rust with Controlled Conditions Inoculation. [Internet] [Masters thesis]. Louisiana State University; 2014. [cited 2019 Nov 22]. Available from: etd-07112014-170420 ; https://digitalcommons.lsu.edu/gradschool_theses/1426.

Council of Science Editors:

Avellaneda Barbosa MC. Screening for Resistance to Sugarcane Brown Rust with Controlled Conditions Inoculation. [Masters Thesis]. Louisiana State University; 2014. Available from: etd-07112014-170420 ; https://digitalcommons.lsu.edu/gradschool_theses/1426


Louisiana State University

2. Avellaneda Barbosa, Mavir Carolina. Identification of Genes Associated with Resistance to Brown Rust in Sugarcane and Prevalence of One Major Gene.

Degree: PhD, Plant Sciences, 2016, Louisiana State University

Development of resistant cultivars is the main control measure against sugarcane brown rust caused by Puccinia melanocephala. Durability is uncertain, since the pathogen possesses adaptive ability to overcome host plant resistance. A differential gene expression study utilizing suppressive subtraction hybridization was conducted to improve understanding of brown rust resistance mechanisms in sugarcane. The expression patterns of 11 unigenes representing biosynthetic pathways, defense-related genes, and signaling genes were analyzed in L 99-233, a cultivar exhibiting quantitative resistance, L 01-299, a resistant cultivar with the major resistance gene Bru1, and two susceptible cultivars, Ho 95-988 and L 09-125, at 24 h, 48 h, 72 h, and 1 week after inoculation with P. melanocephala using (semi)quantitative RT-PCR. All genes analyzed for their expression showed message accumulation upon infection in susceptible and resistant cultivars, but the maintenance of high amounts of mRNAs of the genes for a prolonged time period appeared to be the most important factor contributing to brown rust resistance. Differences in the time-course of gene expression were detected between L 01-299 and L 99-233 suggesting variable mechanisms for resistance between the cultivars. Molecular markers were used to screen the World Collection of Sugarcane and Related Grasses (WCSRG) for Bru1 to determine its distribution and frequency in Saccharum species and related genera. A total of 1,282 clones were screened. Bru1 was distributed across the Saccharum complex, but the frequency varied among species. Bru1was more prevalent in S. robustum clones (59.1%), whereas it occurred in low frequency and exhibited the highest level of variability in clones of S. spontaneum (18.8%). Bru1 frequency was highest in the two secondary cultivated species, S. barberi (79.3%) and S. sinense (71.8%). The frequency of Bru1 detection was 26.4% and 21.0% for S. officinarum and interspecific hybrid clones, respectively. The characterization of the WCSRG for Bru1 distribution and prevalence will complement efforts to characterize diversity in the Saccharum complex for the expected expanded use of marker-assisted selection in the future. Selection for quantitative resistance in combination with Bru1 could allow breeding programs to develop sugarcane cultivars with effective and durable resistance against brown rust.

Subjects/Keywords: marker-assisted selection; Bru1; Brown Rust; Sugarcane

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Avellaneda Barbosa, M. C. (2016). Identification of Genes Associated with Resistance to Brown Rust in Sugarcane and Prevalence of One Major Gene. (Doctoral Dissertation). Louisiana State University. Retrieved from etd-04112016-135419 ; https://digitalcommons.lsu.edu/gradschool_dissertations/3645

Chicago Manual of Style (16th Edition):

Avellaneda Barbosa, Mavir Carolina. “Identification of Genes Associated with Resistance to Brown Rust in Sugarcane and Prevalence of One Major Gene.” 2016. Doctoral Dissertation, Louisiana State University. Accessed November 22, 2019. etd-04112016-135419 ; https://digitalcommons.lsu.edu/gradschool_dissertations/3645.

MLA Handbook (7th Edition):

Avellaneda Barbosa, Mavir Carolina. “Identification of Genes Associated with Resistance to Brown Rust in Sugarcane and Prevalence of One Major Gene.” 2016. Web. 22 Nov 2019.

Vancouver:

Avellaneda Barbosa MC. Identification of Genes Associated with Resistance to Brown Rust in Sugarcane and Prevalence of One Major Gene. [Internet] [Doctoral dissertation]. Louisiana State University; 2016. [cited 2019 Nov 22]. Available from: etd-04112016-135419 ; https://digitalcommons.lsu.edu/gradschool_dissertations/3645.

Council of Science Editors:

Avellaneda Barbosa MC. Identification of Genes Associated with Resistance to Brown Rust in Sugarcane and Prevalence of One Major Gene. [Doctoral Dissertation]. Louisiana State University; 2016. Available from: etd-04112016-135419 ; https://digitalcommons.lsu.edu/gradschool_dissertations/3645

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