Pathogenic Variation of Phakopsora pachyrhizi Isolates on Soybean in the United States from 2006 to 2009

Twizeyimana, M.; Hartman, G. L.

doi:10.1094/pdis-05-11-0379

Cited by 40 publications

(51 citation statements)

References 34 publications

(19 reference statements)

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“…The data revealed a large difference in the rust reactions of Rpp1-carrying PI 200492 and PI 587880A; PI 587880A possesses a different Rpp1 allele compared with PI 200492, Rpp1-b (Ray et al 2009, Yamanaka et al 2015a). The reactions of PI 200492 and PI 587880A to most South American rust populations were evaluated as being susceptible and resistant, respectively, whereas those to the US isolates were evaluated as being resistant and susceptible, respectively (Paul et al 2015, Twizeyimana & Hartman 2012. In contrast, the P. pachyrhizi isolates collected in Alabama in 2004 induced a susceptible reaction in Rpp1-carrying PI 200492.…”

Section: Discussionmentioning

confidence: 99%

Pathogenic Variation of South American Phakopsora pachyrhizi Populations Isolated from Soybeans from 2010 to 2015

Akamatsu

Yamanaka

Soares

et al. 2017

JARQ

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Soybean rust caused by Phakopsora pachyrhizi is one of the most serious economic threats to soybean production in South America. A previous study using South American P. pachyrhizi populations collected between 2007/2008 and 2009/2010 revealed the pathogenic diversity in Argentinean, Brazilian, and Paraguayan rust populations. Because such pathogenic diversity has been a major constraint to the breeding program for soybean rust resistance, pathogen populations were continuously monitored throughout the 2010/2011 to 2014/2015 seasons using the same method of evaluating pathogenicity as used in the previous study. None of the 83 P. pachyrhizi samples collected from the three countries from 2010/2011 to 2014/2015 yielded identical pathogenicity patterns in the 16 differentials, thus demonstrating the pathogenic diversity of more recent South American rust populations. Cluster analysis using a total of 145 rust populations from 2007 to 2015 demonstrated that the Argentinean, Brazilian, and Paraguayan populations were not assigned to three distinct country-based groups. The analysis indicated that a majority of South American populations differed in pathogenicity compared with Japanese rust races. The rates of resistance to the rust populations varied among the 13 differentials carrying Rpp genes; the most effective resistance gene was Rpp1-b followed by Rpp5, and the least effective was Rpp1.

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Section: Discussionmentioning

confidence: 99%

Pathogenic Variation of South American Phakopsora pachyrhizi Populations Isolated from Soybeans from 2010 to 2015

Akamatsu

Yamanaka

Soares

et al. 2017

JARQ

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“…The soybean-P pachyrhizi interaction has been reviewed in depth elsewhere (7). Briefly, isolate differences were first recognized in Taiwan in 1966 (15) and further differentiated in Australia (4,5,16), Japan (33), the United States-based on im ported isolates before the 2004 introduction into the United States (3) and after the 2004 introduction (2,24,27)-and Nigeria (30). Most of these reports differentiated isolates based on virulence records of compatible and incompatible reactions.…”

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confidence: 99%

“…More recent studies have focused on isolates from re cent introductions in Nigeria and the United States and have taken similar measurements, including the number of uredinia per lesion or uredinia per unit of leaf tissue, to quantify differences among isolates representing different geographic and temporal origins (2,23,24,27,30). P. pachyrhizi isolates from two earlier studies, one completed based on isolates collected in Nigeria (30) and the other based on U.S. isolates (27), were also used in the current study. In Nigeria, 116 isolates were categorized into seven pathotype groups based on the number of sporulating uredinia per square centimeter on soybean genotypes with the resistance genes Rppl to -4 and two susceptible soybean genotypes.…”

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Use of Quantitative Traits to Assess Aggressiveness of Phakopsora pachyrhizi Isolates from Nigeria and the United States

et al. 2014

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Twizeyimana, M., Ojiambo, P. S., Bandyopadhyay, R., and Hartman, G. L. 2014. Use of quantitative traits to assess aggressiveness of Phakopsora pachyrhizi isolates from Nigeria and the United States. Plant Dis. 98:1261-1266. Soybean rust, caused by Phakopsora pachyrhizi, is one of the most important foliar diseases of soybean worldwide. The soybean-P. pach yrhizi interaction is often complex due to genetic variability in host and pathogen genotypes. In a compatible reaction, soybean genotypes produce tan-colored lesions, whereas in an incompatible reaction soybean genotypes produce an immune response (complete resistance) or reddish-brown lesions (incomplete resistance). In this study, in total, 116 and 72 isolates of P. pachyrhizi from Nigeria and the United States, respectively, were compared based on six quantitative traits to assess their aggressiveness on two soybean genotypes. All isolates produced reddish-brown lesions on plant introduction (PI) 462312 and tan lesions on TGx 1485-ID. The number of days after inoculation to first appearance of lesions, uredinia, and sporulation, along with the number of lesions and sporulating uredinia per square centimeter of leaf tissue, and the number of uredinia per lesion, were significantly (P < 0.001) different between the two soybean genotypes for all isolates from each country. The number of days to first appearance of lesions, uredinia, and sporulation were greater on PI 462312 than on TGx 1485-ID for all the test isolates. Similarly, the number of lesions and spomlating uredinia per square centimeter, and the number of uredinia per lesion were lower on PI 462312 than on TGx 1485-ID. For both soybean genotypes, the number of sporulating uredinia per square centimeter significantly (P = 0.0001) increased with an increase in the number of lesions per square centimeter. Although the slope of the regression of sporulating uredinia on number of lesions was greater (P < 0.0001) when TGx 1485-ID was inoculated with Nigerian isolates compared with U.S. isolates, slopes of the regression lines did not differ significantly (P > 0.0675) when PI 46312 was inoculated with Nigerian or U.S. isolates. This is the first study that used a large num ber of isolates from two continents to assess aggressiveness of P. pach yrhizi using multiple traits in soybean genotypes with contrasting types of disease reaction. Soybean rust, caused by Phakopsora pachyrhizi Syd., is one of the most important diseases of soybean worldwide. Yield losses result from severe infection, defoliation, and premature maturation (8). Soybean rust can be managed with fungicides (12,18,20) and, partially, by some cultural practices; for example, the use of resistant cultivars (7) and, if possible, alteration of planting dates (28).Three infection types have been used to describe the soybean-P. pachyrhizi interaction: (i) type 0, immune, with no visible infec tion; (ii) type RB, red-brown lesions, with either no uredinia or only sparsely sporulating uredinia; and (iii) type TAN, tan lesions, usually with many ured...

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“…The differentials EC-241778 and JS-335 individually recorded no reaction to 14 and 16 different isolates, respectively. Twizeyimana and Hartman (2012) and Maphosa et al (2013) in the case of soybean rust. The clustering of different isolates based on morphological traits clearly indicated the presence of three pathotypes under Indian conditions.…”

Section: Resultsmentioning

confidence: 99%

Prevalence of pathotypes of Phakopsora pachyrhizi Syd. causing Asian soybean rust in India

Devaraj¹,

Jahagirdar²,

Basavaraja

2016

SL J Food & Agric

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Soybean rust caused by Phakopsora pachyrhizi Syd. is a potential disease causing severe losses in yield and oil quality of soybean [Glycine max (L.) Merr.]. The physiological variability studies were carried out for 25 isolates collected from different growing environment of Karnataka, India during Kharif 2010-2012. Morphological and cultural characters of 25 isolates were studied under identical condition. Among 25 isolates, the maximum uredospore size was found in Ugarkhurd isolate (90.93  70.05 m). The differential JS-335 reacted to the maximum of eight isolates, and isolate Rayanal produced both RB and TAN reaction on most of the differentials. In the clustering of different isolates into pathotypes, the cluster analysis indicated the expression of eight isolates on differential JS-335 and there was no expression of all the isolates on differential PI-459024B. In cluster-II, nine isolates expressed on PI-200492, while one isolate expressed on JS-335. In cluster-III, 23 isolates expressed on PI-459024B and 12 isolates expressed on PI-200492. Hence, this study described the three pathotypes that causes soybean rust in India namely, Cluster I-Reddish Brown (RB) lesion producing pathotypes, Cluster II -TAN lesion producing pathotypes and Cluster III -Mixed or RB + TAN producing pathotypes. This information could further be used for identification of race pattern in Karnataka and other major rust prone areas of India.

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Pathogenic Variation of Phakopsora pachyrhizi Isolates on Soybean in the United States from 2006 to 2009

Abstract: Twizeyimana, M., and Hartman, G. L. 2012. Pathogenic variation of Phakopsora pachyrhizi isolates on soybean in the United States from 2(X)6 to 2009. Plant Dis. 96;75-8L

Cited by 40 publications

References 34 publications

Pathogenic Variation of South American <i>Phakopsora pachyrhizi</i> Populations Isolated from Soybeans from 2010 to 2015

Pathogenic Variation of South American <i>Phakopsora pachyrhizi</i> Populations Isolated from Soybeans from 2010 to 2015

Use of Quantitative Traits to Assess Aggressiveness of Phakopsora pachyrhizi Isolates from Nigeria and the United States

Prevalence of pathotypes of <em>Phakopsora pachyrhizi</em> Syd. causing Asian soybean rust in India

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