Resistance to Soybean Rust in common bean

Resistance to Soybean Rust in common bean M. A. Pastor-Corrales USDA-ARS Soybean Genomics and Improvement Laboratory Beltsville Agricultural Research Center Beltsville, Maryland

Some Salient Soybean Attributes Rust of Soybean rust Moves swiftly A very aggressive plant pathogen Causes very severe yield losses and damage to soybean All commercial soybean cultivars are Susceptible Broad host range Potentially an important disease of other leguminous crops

Soybean Rust Reports Japan 1902 Brazil 2002 Australia 1934 Argentina 2002 Hawaii 1994 Bolivia 2003 Uganda 1996 Uruguay 2004 Zimbabwe 1998 USA 2004 Nigeria 1999 Mexico 2005 South Africa 2001 Ghana 2006 Paraguay 2001 D.R. Congo 2007

Premature defoliation of soybeans by Soybean Rust (Brazil)

Hosts of Soybean Rust LEGUMES (Papilionoideae) Cultivated Crops: Glycine max (soybeans) Phaseolus vulgaris (Dry and Snap beans; e.i., i.e.., kidney beans) Phaseolus lunatus (lima and butter beans) Vigna unguiculata (cowpeas) Cajanus cajan (pigeon peas) Pachyrhizus erosus (yam bean, jicama) Ornamental plants: Hyacinth bean, lupine, royal poinciana Wild hosts: Kudzu, sweet clover

Some Soybean Salient Attributes Rust of Soybean rust Originated in Asia Caused by Phakopsora pachyrhizi A very aggressive plant pathogen Moves swiftly Causes very severe yield losses and damage to soybean Broad host range Potentially an important disease of other leguminous crops

SBR has been reported infecting common beans under field conditions South Africa Plant Disease, February 2005 United States Plant Disease, July 2006 Argentina Plant Disease, January 2007 Brazil Various reports, 2006, 2007

SBR - Symptoms caused by Phakopsora pachyrhizi on Phaseolus vulgaris Bean rust symptoms caused by Uromyces appendiculatus on Phaseolus vulgaris

The common bean (Phaseolus vulgaris) The most important legume for direct human consumption in the world Seed of dry beans Consumed as Pods of snap beans

Navy Dark Red Kidney

Studying the differential Response of Common Bean to SBR Isolates Little information on the interaction of individual isolates of P. pachyrhizi with common bean germplasm 16 common bean cultivars challenged with six isolates of the SBR pathogen Isolates were from Asia, Africa, Latin America

Differential Response of Common Bean Cultivars to SBR Isolates Emphasis on beans with genes for resistance to the common bean rust Uromyces appendiculatus Work was conducted under GH conditions in the USDA-ARS Foreign Disease-Weed Science Research Unit BSL-3 Containment greenhouse at Ft. Detrick, MD

Bean cultivars inoculated with six Phakopsora pachyrhizi isolates Bean Cultivar Bean Type Resistance Gene Pinto 114 Dry bean None Aurora Dry bean Ur-3 Early Gallatin Snap bean Ur-4 Mexico 309 Dry bean Ur-5 Golden White Wax Snap bean Ur-6 PI 181996 Dry bean Ur-11 CNC Dry bean Ur-C?, Ur-N? PI 260418 Dry bean Ur-P?,Ur- I?

ARS bean germplasm lines inoculated with six Phakopsora pachyrhizi isolates Bean Cultivar Bean Type Resistance Gene BelMiDak-RMR-10 Dry bean-ars/navy Ur-4, -11 BelNeb-RR-1 Dry Bean ARS/GN Ur-5, -6, -7 BelMiNeb-RMR-5 Dry bean-ars/gn Ur-4, -6, -11 BelMiNeb-RMR-7 Dry bean-ars/gn Ur-3, -4, -11 BelDak-RR-2 Dry bean-ars/pinto Ur-3, -6, CNN BelDakMi-RMR-14 Dry bean-ars/pinto Ur-3, -4, -11 BelMiNeb-RMR-8 Dry bean-ars/gn Ur-3, -4, -6, -11 BelDakMi-RMR-18 Dry bean-ars/pinto Ur-3, -4, -6, -11

Soybean cultivars - Checks Soybean Accession Resistance genes PI 200492 (Komata) Rpp1 PI 230970 Rpp2 Ina None; Mod. Susc. PI 459025B (Bing-Nan) Rpp4

Six Isolates of Phakopsora Pachyrhizi used in this study TW72-1 Taiwan TW80-2 Taiwan TH01-1 Thailand ZM01-1 Zimbabwe BZ01-1 Brazil PG01-2 Paraguay

Soybean Rust-Soybean Interactions Red Brown HR Necrotic spot Tan Susceptible

Soybean Rust Severity Scale 1-5 Scale 1 = No visible lesions 2 = Few Scattered lesions present 3 = Moderate number of lesions on at least part of the leaf 4 = Abundant number of lesions on at least part of the leaf 5 = Prolific lesion development over most of the leaf

Soybean Rust Sporulation Scale 1-5 Scale 1 = No sporulation 2 = Present on but less than 25% of a fully sporulating lesion 3 = Sporulation equal to 26 t0 50% of a fully sporulating lesion 4 = Sporulation equal to 51 t0 75% of a fully sporulating lesion 5 = Sporulation equal to a fully sporulating lesion

Differential Response of common bean to Phakopsora pachyrhizi As a group, common cultivars appeared to have resistance to SBR None were immune When compared with Soybean cv. Ina, were similar in severity but had less sporulation

Mean Soybean Rust severity and Sporulation of 16 common Bean Cultivars inoculated with six isolates of SBR pathogen _ X=2.9 _ X=3.1 _ X=2.8 _ X=4.2

5.0 4.5 4.0 3.5 3.0 2.5 2.0 1.5 1.0 Common bean cultivars Aurora, CNC, and PI 181996 had lower SBR severities than soybean Ina Soybean Rust Severity 2.7 3.3 2.9 2.9 3.0 3.0 2.9 3.2 2.8 2.4 2.9 3.2 3.4 2.7 2.8 2.8 3.1 3.1 3.0 3.5 Aurora BDM-RMR-14 BDM-RMR-18 BelDak-RR-2 BMD-RMR-10 BMN-RMR-5 BMN-RMR-7 BMN-RMR-8 BelNeb-RR-1 CNC Early Gallatin Golden W.W. Mexico 309 PI 181996 PI 260418 Pinto 114 Ina PI 200492 PI 230970 PI 459025B Common beans and Soybeans Mean severity

Common bean cultivars Aurora, CNC, PI 181996, and Pinto 114 had significantly lower SBR sporulation than soybean Ina Soybean rust sporulation 5.0 4.5 4.0 3.5 3.0 2.5 2.0 1.5 1.0 2.3 4.2 3.6 2.4 3.4 3.7 2.8 3.7 2.7 3.3 4.8 4.8 1. 6 3.2 2.1 2.6 2.0 2.0 3.0 3.5 Aurora BDM-RMR-14 BDM-RMR-18 BelDak-RR-2 BMD-RMR-10 BMN-RMR-5 BMN-RMR-7 BMN-RMR-8 BelNeb-RR-1 CNC Early Gallatin Golden W.W. Mexico 309 PI 181996 PI 260418 Pinto 114 Ina PI 200492 PI 230970 PI 459025B Common beans and soybeans Mean sporualation

Differential Response of Common Bean Cultivars to SBR Isolates Cultivar-Isolate interaction was significant All common bean cultivars did not respond similarly to each SBR isolate for both, severity and sporualtion

Bean Cultivar - SBR Isolate Interaction Severity

Bean Cultivar - SBR Isolate Interaction Sporulation

Differential Response of Common Bean to SBR Isolates Summary Bean cultivars CNC, PI 181996, Aurora and Pinto 114 were the most resistant to all six isolates of SBR pathogen These cultivars had lower severity, less sporulation, and consistent RB (resistant) lesions

Differential Response of Common Bean to SBR Isolates Summary A differential response was observed among bean cultivars with a cultivarisolate interaction for severity and sporulation Resistance to SBR in common bean was independent of the resistance to Uromyces appendiculatus Pinto 114, universally susceptible to U. appendiculatus Resistant to SBR BDM-RMR-18 with four genes for resistance to U. p. one of the most susceptible to SBR

Inheritance of Resistance to Soybean Rust in common bean Severity reaction to Phakopsora pachyrhizi isolates BZ01-1 PG01-1 TH01-1 TW72-1 TW80-2 ZM01-1 CNC 2.1 2.3 2.5 2.6 2.4 2.6 Mex. 309 3.7 3.7 3.0 3.4 3.4 3.4

4.0 3.5 3.0 2.5 2.0 1.5 CNC Mexico 309 1.0 0.5 0.0 BZ01-1 PG01-1 TH01-1 TW72-1 TW80-2 ZM01-1 Reaction to Phakopsora pachyrhizi isolates Soybean Rust Severity Rating

Inheritance of Resistance to Soybean Rust in common bean Soybean Rust Sporulation Sporulation to Phakopsora pachyrhizi isolates BZ01-1 PG01-2 TH01-1 TW72-1 TW80-1 ZM01-1 CNC 1.5 1.5 2.1 1.3 1.3 1.8 Mex. 309 3.4 2.5 2.5 1.8 3.1 2.6

3.5 3.0 2.5 2.0 1.5 CNC Mexico 309 1.0 0.5 0.0 BZ01-1 PG01-2 TH01-1 TW72-1 TW80-1 ZM01-1 Reaction to Phakopsora pachyrhizi isolates

Inheritance of SBR resistance in common bean CNC Cross: Mexico 309 (S) x CNC (R) Two F 2 populations P1: 117 F 2 plants P2: 124 F 2 plants All F 2 plants, R and S parents and soybean check inoculated with Brazilian isolate (BZ-1-1)

Total 117 124 241 F 2 Mexico 309 x CNC Phenotype based on Severity First batch Second batch Both Batches Grade # # # 2 6 10 16 3 63 61 124 4 37 45 82 5 11 8 19

Segregation for Resistance in CNC to Phakopsora pachyrhizi (BZ01-1) Observed R S Expected Ratio χ P F 2 140 101 9R:7S 0.01 0.9 F 2 140 101 3R:1S 13.6 F 2 140 101 13R:3S 45.3

Resistance in CNC to SBR Results suggest that resistance in CNC is controlled by the interaction of two genes Complete dominance at both gene pairs Either recessive homozygote is epistatic to the effects of the other gene A_B_ = 9 Resistant A_bb = 3 Susceptible aab_ = 3 Susceptible Aabb = 1 Susceptible

Summary Common beans appear to be much less susceptible to ASR than Soybeans Resistance in common bean offers a number of opportunities for further studies with potential of leading to new genetic options for the control of the ASR pathogen Further studies are needed to understand and characterize the resistance genes in common bean to the ASR pathogen Research should benefit dry and snap beans and possibly soybeans

Present and Future SRB Work Search for molecular markers linked to SBR resistance genes in CNC Evaluate common bean core collection with selected isolates of SBR, include snap beans and commercial dry beans Search for additional SBR resistance genes & possible vulnerabilities If SBR resistance genes in common bean could be cloned - they could be used to genetically engineer soybeans with resistance to ASR

Glen Hartman Monte Miles Reid Frederick Morris Bonde