Mallu, T S and Irafasha, G and Mutinda, S and Owuor, E and Githiri, S M and Odeny, D A and Runo, S (2022) Mechanisms of pre-attachment Striga resistance in sorghum through genome-wide association studies. Molecular Genetics and Genomics, 297. pp. 751-762. ISSN 1617-4623
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Witchweeds (Striga spp.) greatly limit production of Africa’s most staple crops. These parasitic plants use strigolactones (SLs)—chemical germination stimulants, emitted from host’s roots to germinate, and locate their hosts for invasion. This information exchange provides opportunities for controlling the parasite by either stimulating parasite seed germination without a host (suicidal germination) or by inhibiting parasite seed germination (pre-attachment resistance). We sought to determine genetic factors that underpin Striga pre-attachment resistance in sorghum using the genome wide association study (GWAS) approach. Results revealed that Striga germination was associated with genes encoding hormone signaling functions, e.g., the Novel interactor of jaz (NINJA) and, Abscisic acid-insensitive 5 (ABI5). This pointed toward abscisic acid (ABA) and gibberellic acid (GA) as probable determinants of Striga germination. To test this hypothesis, we conditioned Striga using: ABA, ABA + its inhibitor fluridone (FLU), GA or water. Unexpectedly, Striga conditioned with FLU germinated after 4 days without SL. Upon germination stimulation using sorghum root exudate or the synthetic SL GR24, we found that ABA conditioned seeds had above 20-fold reduction in germination. Conversely, FLU conditioned seeds recorded above 20-fold increase in germination. Conditioning with GA reduced Striga seed germination 1.5-fold only in the GR24 treatment. Germination assays using seeds of a related parasitic plant (Alectra vogelii) showed similar degrees of stimulation and reduction of germination by the hormones further affirming the hormonal crosstalk. Our findings have far-reaching implications in the control of some of the most noxious pathogens of crops in Africa.
| Item Type: | Article |
|---|---|
| Divisions: | Research Program : East & Southern Africa |
| CRP: | UNSPECIFIED |
| Uncontrolled Keywords: | Abscisic acid, Gibberellic acid, GWAS, Hormonal crosstalk, Parasitic plants, Pre-attachment resistance, Sorghum, Striga, Strigolactone |
| Subjects: | Mandate crops > Sorghum Others > Genetics and Genomics |
| Depositing User: | Mr Nagaraju T |
| Date Deposited: | 12 Feb 2024 04:39 |
| Last Modified: | 12 Feb 2024 04:39 |
| URI: | http://oar.icrisat.org/id/eprint/12453 |
| Official URL: | https://link.springer.com/article/10.1007/s00438-0... |
| Projects: | UNSPECIFIED |
| Funders: | NAS and the United States Agency for International Development |
| Acknowledgement: | The research leading to these results received funding from the National Academies of Science (NAS) under the Partnerships for Enhanced Engagement in Research (PEER) program, Grant/Award Number: PGA- 2000008288; NAS and the United States Agency for International Development, Grant/Award Number: AID-OAA-A-11-00012. ICRISAT, Eastern and Southern Africa provided funding to conduct DArT seq. TM’s PhD fellowship is sponsored by the Pan African University (PAUSTI) through an African Union Initiative. |
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