Browsing by Author "Runo Steven"

Now showing 1 - 6 of 6
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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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    Cholera in Sub-Saharan Africa: Unveiling Neglected Drivers and Pathways to Elimination
    (PLOS, 2025) Siamalube Beenzu; Ehinmitan Emmanuel; Runo Steven; Maina Ngotho; Onguso Justus
    Cholera is a virulent infectious disease caused by the Gram-negative, comma-shaped bacteria Vibrio cholerae, after ingesting contaminated food and/or water. If left untreated, it can kill within 5 days. Since mid-2021 the world has recorded a notable increase in the seventh cholera pandemic, with high case fatality rate especially in Sub-Saharan Africa. Oral cholera vaccines are established but not readily available on the market, or if they are, they are not pocket friendly for low-resource-income countries. Hence, with the advent of green factory biotechnology, plant-derived edible vaccines are such a promising approach to supplement conventional vaccine methods. Human travellers are often the major transmitters as they move from region to region. Poor sanitation and inadequate clean water supply are services not readily available in most Sub-Saharan African countries, coupled with insufficient surveillance services, lack of early detection facilities, and the public not having ample awareness concerning sanitation and hygiene. This article highlights the epidemiology of cholera in Africa and expounds on what drives the outbreaks of cholera in this region. The discussion provides an in-depth analysis of the factors leading to the forsaken cholera drivers, emphasizing economic factors, culture, and environmental influences, particularly within the Sub-Saharan African communities. It presents a strategic blueprint approach that includes public health awareness, community participation, government involvement, and exploring emerging research tools. By merging these proposals into a unified context, a collective and practical methodology would be established to tackle the impact of cholera epidemiology that has been sidelined in Sub-Saharan Africa
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    Evaluation of Formulated Strigolactone Analogs for Striga Management in Kenyan Agriculture
    (Elsevier B.V, 2025) Muhammad Jamil; Mutinda Sylvia; Jian You Wang; Barminga Damaris; Mwihaki Agnes; Navangi Lynet; Okiyo Teresa O.; Patil Rohit H.; Ngatia Titus; Mudavadi Patrick; Runo Steven; Al-Babili Salim
    Striga hermonthica, an obligate root parasitic weed affecting cereal crops, poses a significant threat to global food security in Sub-Saharan Africa (SSA). Germination of Striga seed largely relies on signaling molecules released by the host roots, mainly strigolactones (SLs). Suicidal germination is an effective strategy for reducing Striga seed banks in infested soils by applying SL analogs in the absence of a host. However, the challenge remains in developing suitably formulated SL analogs for field application. In this report, we assessed the activity of two SL analogs, MP3 and Nijmegen-1, in both granular and liquid formulations in laboratory and greenhouse settings, and conducted mini-field and field trials to evaluate their effectiveness under farmers’ conditions, using maize as the host crop in Kenyan agriculture. We observed a significant induction of Striga seed germination reaching up to 56 % in laboratory germination bioassays and a reduction in Striga emergence by up to 77 % in greenhouse pot studies. In mini- and field trials in different infested fields, we recorded up to 80 % and 65 % reduction in Striga emergence, respectively. In conclusion, the formulated SL analogs demonstrate significant potential to reduce Striga infestation in maize fields in Kenya and are promising candidates for use by farmers due to their simplicity, ease of handling, stability, and effectiveness
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    Parasitic plants are models for examining global food security,biodiversity loss and host–parasite evolution, in achanging world
    (John Wiley & Sons, 2024) Runo Steven; Wicke Susann; Thorogood Chris
    Parasitic plants devastate crop productivity around the world, threatening food and nutritional security for millions. In this special issue of Plants People, Planet, we provide a systematic analysis of some of the most devastating parasitic plants that threaten global food security focusing on (i) witchweeds, (ii) broomrapes and (iii) vampireweeds. Witchweeds—members of the genus Striga—have earned themselves the nickname ‘cereal killers’ because of their devastating destruction of Africa's most staple cereals, including maize, sorghum, millets and upland rice. Striga is a highly successful parasite, the lifecycle of which is tightly synchronised with that of its host (Runo & Kuria, 2018). Central to this synchronisation is its ability to detect and locate would be hosts through biomolecules—predominantly strigolactones—emitted from the host (Al-Babili & Bouwmeester, 2014; Matusova et al., 2005). Ironically, the reliance of Striga on strigolactones (SLs) is also its Achilles' heel as this presents opportunities for control through manipulation of communication exchange. One approach involves growing Striga alongside a false host that releases SLs, which trigger Striga germination but fail to support its growth or infection (Khan et al., 2011). Another method uses germination stimulants applied to bare fields to induce Striga germination without a host (Jamil et al., 2022, 2024; Kountche et al., 2019). These methods are referred to as ‘suicidal germination’. Additionally, breeding host crops that produce insufficient or less potent SLs can also help manage Striga infestations. These strategies have made SLs a central focus of research for Striga control...
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    PlantGENE Report on Panel Discussion: Advancing Plant Biotechnology in Africa
    (Springer, 2025) Malzahn Aimee A.; Songstad Nicole; Tripathi Leena; Ihuoma Okwuonu; Sithole‑Niang Idah; Runo Steven; Wagaba Henry; Kouassi Modeste; Kaeppler Heidi; Gordon‑Kamm William; Keunsub Lee; Wayne Parrott; Nigel Taylor; Rogers Christian; Gafney Jim; Van Eck Joyce; Veena Veena
    This report provides an overview of the content and data collected from the “Successes, Challenges, and Opportunities Plant Transformation Research in Africa” panel discussion. Organized by PlantGENE, this event brought together scientists and stakeholders across the globe to examine the complex challenges and emerging opportunities in plant transformation research in laboratories across Africa. The discussion, rooted in insights from a panel of six leading scientists, highlights critical issues including restrictive regulatory environments, prohibitive costs, and the inconsistent availability of essential research materials. Additionally, the pervasive “brain drain” phenomenon, where skilled researchers leave the continent for better opportunities, exacerbates the difculties faced by African scientists. Despite these challenges, the report also identifes signifcant advancements, particularly in the growing recognition of African leadership within universities and national agricultural research systems (NARS). These institutions, supported by highly skilled faculty and motivated graduate students, are producing high-quality research that contributes to global scientifc knowledge. The panelists emphasized the necessity of creating an environment that encourages African scientists to remain on the continent and address local challenges through innovative research. Strengthening intra-African networks and fostering collaborations with the global scientifc community are proposed as essential strategies to achieve this. This report underscores the critical need for substantial investments from both global and African organizations, working with African governments, to support these eforts. Furthermore, it calls for science-based decision-making and fair regulatory frameworks to align with unique opportunities and risks associated with technological advancements in Africa. This paper details the observations of six panelists and analyzes the results of attendee surveys in order to document these challenges and opportunities while advocating for sustained investment and strategic partnerships to build a thriving bioeconomy across Africa.
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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.