Evaluation of the applicability of classical and molecular methods for diagnosing the phytopathogen Bipolaris zeicola (Stout) Shoemaker in laboratory conditions

Leaf blight of maize Cochliobolus carbonum R.R. Nelson (= Bipolaris zeicola (Stout) Shoemaker) is a quarantine pest for the Russian Federation and some other countries, capable of infecting not only cereals, but also other agricultural plants. The species is spread in many regions of corn cultivation on all continents, has a high harmfulness under certain environmental conditions, causing massive epiphytoties and severe damage to cultivated plants. Imported regulated seed products of corn plants (Zea mays L.) poses a high phytosanitary risk of introduction of invasive species into the Russian Federation and their spread within it. Therefore, timely diagnosis, based on the correct approach to the application of methods for the detection and identification of quarantine pests, is an important criterion for mycological research. The article presents data on the species of the genus Cochliobolus detected from regulated corn plants in the course of laboratory studies for the period 2017–2021. The classical polymerase chain reaction (PCR) method was tested using species-specific primers (Bz-F/Bz-R) developed by Kang et al. In the course of the research, working criteria were determined, according to which it was found that the test system under study is characterized by high analytical sensitivity and specificity and is applicable for laboratory testing of the quarantine species B. zeicola in incoming regulated corn plants. The article also describes the classical cultural and morphological methods for identifying the B. zeicola species, carried out a genetic analysis of the isolates in the region of the internal transcribed spacer ITS4-5, 8S-ITS5. A comparative morphological analysis of the target and closely related species occurring on corn plants is given.

1. Александров И., 1992. Проблема южного гельминтоспориоза кукурузы и способы ее решения. – Проблемы карантина растений, № 2: 103–107.

2. Боровская М., Матичук В., 1990. Новый вид гельминтоспориозной пятнистости на кукурузе в Молдавии. – Изв. АН Молдавской ССР: 25–38.

3. Мартынюк Т., 2003. Возбудители грибных болезней листьев кукурузы (Zea mays) в Приморском крае. – Микология и фитопатология, 37 (3): 80–85.

4. Cipollone J. et al., 2020. First report of Bipolaris zeicola on barley worldwide. – Crop Protection, Vol. 135: 105188. URL: https://doi.org/10.1016/j.cropro.2020.105188.

5. Hooker A., 1974. Field reaction of corn inbreds to Helminthosporium leaf spot. – Plant Dis. Reptr., 58: 909–911.

6. Kang I. et al., 2018. Simple Detection of Cochliobolus Fungal Pathogens in Maize. – Plant Pathol J., 34 (4): 327–334. URL: https://doi.org/10.5423/PPJ. FT.10.2017.0209.

7. Manamgoda D. et al., 2011. Cochliobolus: an overview and current status of species. –Fungal Diversity, Vol. 51: 3–42. URL: https://doi.org/10.1007/s13225-011-0139-4.

8. Manamgoda D. et al., 2014. The genus Bipolaris. – Studies in mycology, Vol. 79: 221–288. URL: https://doi.org/10.1016/j.simyco.2014.10.002.

9. Rabie A. El-Shafey et al., 2018. Incidence and Molecular Identification of Cochliobolus carbonum as Causal Organism of Rice Seedling Blight. – Beni-Suef University Journal of Basic and Applied Sciences, 7 (4): 652–662.

10. Ullstrup A., 1944. Further studies on a species of Helminthosporium parasitizing corn. – Phytopathology, Vol. 34: 214–222.

11. White T. et al., 1990. Amplification and direct sequencing of fungal ribosomal RNA genes for phylogenetics. In: PCR Protocols: A Guide to Methods and Applications. – New York: Academic Press, 315–322 p.

12. Справочник по карантинному фитосанитарному состоянию территорий государств – участников СНГ на 01.01.2018. – URL: https://vniikr.ru/files/spravochnik/%D0%BD%D0%B0%2001.01.2019. pdf (дата обращения: 02.08.2022).

13. EPPO Global Database. – URL: https://gd.eppo.int/taxon/COCHCA/distribution (дата обращения: 02.08.2022).

14. Index Fungorum. – URL: http://www.speciesfungorum.org (дата обращения: 02.08.2022).

15. National Center for Biotechnology Information. – URL: http://www.ncbi.nlm.nih.gov (дата обращения: 02.08.2022).