Browsing by Author "Kibet Willy"

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    Cell Wall Dynamics in the Parasitic Plant (Striga) and Rice Pathosystem
    (MPMI, 2025) Barminga Damaris; Mutinda Sylvia; Mobegi Fredrick M.; Kibet Willy; Hale Brett; Anami Sylvester; Wijeratne Asela; Bellis Emily S.; Runo Steven
    In the plant-plant pathosystem of rice (Oryza sativa) and the parasitic plant Striga hermonthica, cell walls from either plant are important defensive and offensive structures. Here, we reveal the cell wall dynamics in both Striga and rice using simultaneous RNA sequencing. We used weighted gene co-expression network analysis to home in on cell wall modification processes occurring in interactions with a resistant rice cultivar (Nipponbare) compared with a susceptible one (IAC 165). Likewise, we compared the cell wall dynamics in Striga infecting resistant and susceptible rice. Our study revealed an intense battlement at the Striga-rice cell walls involving both parasite (offense) and host (defense) factors, the outcome of which makes the difference between successful or failed parasitism. Striga activates genes encoding cell wall-degrading enzymes to gain access to the host, expansins to allow for cell elongation, and pectin methyl esterase inhibitors for rigidity during infection. In the susceptible host, immune response processes are not induced, and Striga-derived cell wall-degrading enzymes easily breach the host cell wall, resulting in successful parasitism. In contrast, the resistant host invokes immune responses modulated by phytohormones to fortify the cell wall through polysaccharides and lignin deposition. Through these processes, the cell wall of the resistant host successfully obstructs parasite entry. We discuss the implications of these findings in the context of practical agriculture in which cell wall modification can be used to manage parasitic plants.
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    Pre- and Post-Attachment Resistance Response of Popular Western Kenya Maize Hybrids to Parasitism by Witchweed (Striga
    (wiley, 2024) Odero Calvins Okoth; Kibet Willy; Oduor Richard Okoth; Dida Mathews Mito; Runo Steven
    Striga hermonthica (Delile) Benth is a root parasitic weed that causes significant crop losses in cereals in the sub-Saharan Africa. Host resistance is a sustainable management approach; however, Striga resistance in maize is rare. Furthermore, hybrids, preferred for high yield and other agronomic traits are more susceptible than local landraces. We sought to determine the responses of popular maize hybrids against Striga infection using in vitro germination and rhizotron assays. We screened 16 maize hybrids commonly cultivated in Kenya against two common Striga ecotypes (Kibos and Alupe) by measuring their (i) ability to induce the germination of S. hermonthica seeds in an in vitro system (pre-attachment resistance) and (ii) ability to resist the attachment and establishment of effective parasitism (post-attachment resistance). Results showed that two maize hybrids H614D and H629 exhibit both pre- and post-attachment resistance comparable to a Striga resistant landrace KSTP'94 used in this study as a resistant check. Other hybrids displayed moderate Striga resistance; DK8031 (pre-attachment resistance) and Duma43, phb30G19 and WH507 (postattachment resistance). Striga virulence, defined as aggressiveness of the parasite— measured by response to germination and host colonisation, was higher for the Kibos ecotype compared to the Alupe ecotype. However, the resistance pattern of maize genotypes remained consistent across the different Striga ecotypes. These results provide a basis for informed decisions on cultivation of various maize hybrids under Striga infestation in western Kenya.