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2025 Vol.70, Issue 4 Preview Page

Original Research Article

A Rapid In Vitro Seedling Assay for Screening Soybean Resistance to Diaporthe longicolla
Guta Rahel Dinsa1
,
Jun Hyoung Jeon2
,
Hyeon Su Lee2
,
Seoyeon Hong2
,
Ok Jae Won2
,
Maharjan Rameswor1
,
Youngnam Yoon3
,
Yun-Woo Jang4*
1Professional Researcher, National Institute of Crop and Food Science, Department of Upland Crop Sciences, Smart Agricultural Technology Division, RDA, Miryang 50424, Korea
2Junior researcher, National Institute of Crop and Food Science, Department of Upland Crop Sciences, Smart Agricultural Technology Division, RDA, Miryang 50424, Korea
3Senior researcher, National Institute of Crop and Food Science, Department of Upland Crop Sciences, Smart Agricultural Technology Division, RDA, Miryang 50424, Korea
4Junior Researcher, Research Policy Planning Division, Research Policy Bureau, Rural Development Administration, Jeonju 54875, Korea
*Corresponding Author
1 December 2025. pp. 267-275
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Abstract

Pod and stem blight, primarily caused by Diaporthe longicolla, is a major disease affecting soybean production worldwide. Accurate and efficient evaluation of disease resistance in soybean cultivars strongly depends on the inoculation technique used. Eight artificial inoculation methods were compared, including cut-seedling, toothpick, stem wound, mycelium contact, mycelium spraying, spore injection, conidial suspension injection, and ascospore inoculation methods, using two virulent D. longicolla isolates on two soybean varieties under controlled conditions. The stems and leaves of three-week-old soybean seedlings were inoculated using the above-mentioned techniques. Disease severity, lesion length, and area under the disease progress curve (AUDPC) were used to assess pathogenicity and disease development. The results revealed differences among inoculation methods, isolates, and soybean varieties. The cut-seedling, toothpick, and stem wound methods consistently induced earlier and more severe symptoms, the highest AUDPC values, and even plant death in some cases. In contrast, the ascospore and mycelium spraying methods produced negligible or no symptoms. The findings highlight the critical influence of the selected inoculation technique on disease expression, providing valuable guidance for optimizing disease resistance screening and pathogenesis studies in soybean breeding programs.

Keywords
Diaporthe longicolla
disease severity
inoculation
pod and stem blight disease
soybean
References
1

Abdelmagid, A., M. Hafez, Y. Lawley, P. K. Rehal, and F. Daayf. 2022. First report of pod and stem blight and seed decay caused by Diaporthe longicolla on soybean in western Canada. Plant Dis. 106 : 1061.

10.1094/PDIS-04-21-0783-PDN
2

Buzdar, M. I., M. J. A. Awan, G. Raza, R. Z. Naqvi, S. Mansoor, and I. Amin. 2025. Potential of conventional and new breeding technologies to manage soybean diseases. Phytopathol. Res. 7 : 49.

10.1186/s42483-025-00338-0
3

Campbell, M. A., Z. Li, and Buck, J. W. 2017. Development of southern stem canker disease on soybean seedlings in the greenhouse using a modified toothpick inoculation assay. Crop Prot. 100 : 57-64.

10.1016/j.cropro.2017.05.026
4

Choi, H. W., H. J. Ryu, Y. H. Lee, Y. W. Jang, H. J. Yi, and S. K. Hong. 2023. First Report of Fusarium ipomoeae Causing Fusarium Wilt on Glycine max in South Korea. Plant Dis. 107 : 2.

10.1094/PDIS-07-21-1499-PDN
5

Chiang, K. S., H. I. Liu, and C. H. Bock. 2017. A discussion on disease severity index values. Part I: warning on inherent errors and suggestions to maximize accuracy. Ann. Appl. Biol. 171 : 139-154.

10.1111/aab.12362
6

Ghimire, K., K. Petrovic, B. J. Kontz, C. A. Bradley, M. I. Chilvers, D. S. Mueller. 2019. Inoculation Method Impacts Symptom Development Associated with Diaporthe aspalathi, D. caulivora, and D. longicolla on Soybean (Glycine max). Plant Dis. 103 : 677-684.

10.1094/PDIS-06-18-1078-RE
7

Hobbs, T. W., A. F. Schmitthenner, G. A. Kuter. 1985. A new Phomopsis species from soybean. Mycologia 77 : 535-544.

10.1080/00275514.1985.12025139
8

Hosseini, B., M. G. Grobner, and T. I. Link. 2024. First report of Diaporthe goulteri on soybean in Germany. J. Fungi (Basel), 10 : 803.

10.3390/jof1011080339590722PMC11595983
9

Hosseini, B., R. T. Voegele, and T. I. Link. 2023. Diagnosis of soybean diseases caused by fungal and oomycete pathogens: existing methods and new developments. J. Fungi (Basel), 9.

10.3390/jof905058737233298PMC10219529
10

Kang, H., N. Park, D. Kim, and I. Choi. 2021. Screening of Soybean Varieties Resistant to Heterodera sojae. J. Environ. Sci. Int. 30 : 347-352.

10.5322/JESI.2021.30.4.347
11

Kang I. J., S. H. Kim Y. W. Seo M. J. Seo H. K. Shim D. B. Shin, and S. Heu. 2015. Effective selection of soybean cultivars to wildfire disease pathogen Pseudomonas amygdali pv. tabaci. J. Crop Sci. Biotechnol. 18 : 279 - 284.

10.1007/s12892-015-0104-y
12

Keeling, B. L. 1982. A seedling test for resistance to soybean stem canker caused by Diaporthe phaseolorum var. caulivora. Phytopathology 72 : 807e809.

10.1094/Phyto-72-807
13

Li, S. 2018. Development of a seedling inoculation technique for rapid evaluation of soybean for resistance to Phomopsis longicolla under controlled conditions. Plant Methods 14 : 81.

10.1186/s13007-018-0348-x30214468PMC6131871
14

Li, Z., B. Zhang, Y. Fu, Y. Suo, Y. Zhang, and J. Feng. 2025. A rapid and efficient in vivo inoculation method for introducing tree stem canker pathogens onto leaves: suitable for large-scale assessment of resistance in poplar breeding progeny. Plant Methods 21 : 41.

10.1186/s13007-025-01360-140128764PMC11934469
15

Mathew, F. M., K. M. Alananbeh, J. G. Jordahl, S. M. Meyer, L. A. Castlebury, and T. J. Gulya. 2015. Phomopsis stem canker: a reemerging threat to sunflower (Helianthus annuus) in the united states. Phytopathology 105 : 990-997.

10.1094/PHYTO-11-14-0336-FI
16

Mena, E., S. Stewart, M. Montesano, and I. Ponce de Leon. 2019. Soybean stem canker caused by Diaporthe caulivora; pathogen diversity, colonization process, and plant defense activation. Front. Plant Sci. 10 : 1733.

10.3389/fpls.2019.0173332117332PMC7011206
17

Olson, T. R., A. Gebreil, A. Micijevic, C. A. Bradley, K. A. Wise, and D. S. Mueller. 2015. Association of Diaporthe longicolla with Black Zone Lines on Mature Soybean Plants. Plant Health Progress 16 : 118-122.

10.1094/PHP-RS-15-0020
18

Petrovic, K., L. Riccioni, V. Djordjevic, S. Balesevic-Tubic, J. Miladinovic, M. Ceran, and D. Rajkovic. 2018. Diaporthe pseudolongicolla: The new pathogen on soybean seed in Serbia. Field Crops Res. 55 : 103-109.

10.5937/ratpov55-18582
19

Petrovic, K., J. Sucur Elez, M. Crnkovic, S. Krsmanovic, M. Rajkovic, and B. Kuzmanovic. 2023. The biochemical response of soybean cultivars infected by Diaporthe species complex. Plants (Basel) 12 : 2896.

10.3390/plants1216289637631108PMC10457839
20

Then, P., L. Lay, A. Ghimire, M. S. Islam, and Y. Kim. 2023. Assessment of Bacterial Wildfire Infection in Soybean Cultivars by Hyperspectral Imaging. J. Agric. Life Environ. Sci. 35 : 259-274.

21

Sedivy, E. J., F. Wu. and Y. Hanzawa. 2017. Soybean domestication: the origin, genetic architecture and molecular bases. New Phytol. 214 : 539-553.

10.1111/nph.14418
22

Shen, W., L. Pan, Y. Fu, Y. Suo, Y. Zhang, and H. Liu. 2024. Comparative study on the effectiveness of three inoculation methods for Valsa sordida in Populus alba var. pyramidalis. Biology (Basel) 13 : 251.

10.3390/biology1304025138666863PMC11047983
23

Shuxian, Li. 2011. Phomopsis Seed Decay of Soybean, Soybean - Molecular Aspects of Breeding, Dr. Aleksandra Sudaric (Ed.), ISBN: 978-953-307-240-1, InTech, Available from: http:// www.intechopen.com/books/soybean-molecular-aspects-of-breeding/phomopsis-seed-decay-of-soybean

24

Sureshbabu, B. M., A. M. Gillen, J. R. Smith, T. Mukaila, S. G. Markell, and F. M. Mathew. 2025. Greenhouse Results Suggest that Disease Severity in Soybean (Glycine max), Caused by Diaporthe longicolla as Both a Stem and Seed Pathogen, May Not Be Correlated. Plant Health Progress 26 : 12-19.

10.1094/PHP-05-24-0042-RS
25

Twizeyimana, M., C. B. Hill, M. Pawlowski, C. Paul, and Hartman, G. L. 2012. A cut-stem inoculation technique to evaluate soybean for resistance to Macrophomina phaseolina. Plant Dis. 96:1210-1215.

10.1094/PDIS-02-12-0126-RE
26

United States Department of Agriculture (USDA). 2025. 2024/2025 Soybeans Production. https://www.fas.usda.gov/data/production/commodity/2222000 Accessed on 20 September, 2025.

27

Zhao, X., Li, K., Zheng, S., Yang, J., Chen, C., Zheng, X. 2022. Diaporthe diversity and pathogenicity revealed from a broad survey of soybean stem blight in China. Plant Dis. 106 : 2892-2903.

10.1094/PDIS-12-21-2785-RE
Information
  • Publisher :The Korean Society of Crop Science
  • Publisher(Ko) :한국작물학회
  • Journal Title :The Korean Journal of Crop Science
  • Journal Title(Ko) :한국작물학회지
  • Volume : 70
  • No :4
  • Pages :267-275
  • Received Date : 2025-10-03
  • Revised Date : 2025-11-22
  • Accepted Date : 2025-11-24
  • DOI :https://doi.org/10.7740/kjcs.2025.70.4.267
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