Abstract. Kuria EK, Machuka J, Runo S. 2019. Maize bioengineering with c-repeat binding factor 1 (CBF1) as a technique for desiccation toleration. Trop Drylands 3: 1-10. Africa is a desiccation inclined continent leading to riskful cultivation particularly to small-scale cultivators who rely on rain-fed agriculture. Maize is the most widely cultivated main crop in Africa with more than 300 million people relying on it as their principal dietdiet fount. Desiccation causes crop fiasco, famine and poverty and this is being aggravated by climate change. There is therefore an obligation to flourish desiccation tolerablish maize. Traditional propagation techniques have been implementedcarried out in the establishment of desiccation tolerablish plants but are restricted by their requirement for labour, time and space, suggesting a limited genetic diversity within genotypes and transition of undesired traits along with the wanted ones. These restrictions are handled by utilizing these techniques along with bioengineering. Desiccation triggers a range of physiological and biochemical reactions in plants at cellular and molecular levels. These reactions include initiation of genes with several usefulness. Plant alteration for expanded desiccation toleration is generally based on the administration of either transcription and/or signaling factors or genes that directly secure plant cells contra water shortage. C-repeat binding factor (CBF) is a transcriptional factor that interacts with the desiccation responsive element (DRE), a cis-acting promoter element that governs gene expression in reaction to desiccation, brine and freezing stress. Over expression of these transcription factors, escalates stress toleration to freezing, desiccation and high brininess. In this study, three maize inbred lines and one hybrid were altered with CBF1 gene and appointed with mannose utilizing the Phosphomannose isomerase (PMI) gene. Genetic alteration was conducted through Agrobacterium tumefaciens and PCR was utilized to ascertain altered plants. Alteration frequency, alteration effectiveness and regeneration effectiveness were equated among the distinct genotypes altered. There were no remarkable dissimilarities in alteration frequency among the four maize genotypes. CML216 had the highest alteration effectiveness and regeneration effectiveness followed by A188. No alleged transgenic plants were regenerated from TL27 and A188×TL18 under the circumstances implemented on acount of their low regenerability. Further molecular analysis and desiccation stress tentatives on the expanded transgenic maize are significant prior to commercial release. Availability of desiccation tolerablish maize would bear a considerable positive collision contra famine particularly in Africa.

Striga is a genus of parasitic plants that poses great danger to livelihoods of millions of smallholder farmers in sub-Saharan Africa by limiting production of staple cereals. The parasite attaches to the roots of the crop and establishes a vascular connection with the host’s xylem vessels in order to access water, organic and inorganic nutrients, leading to stunted growth and death of the infected plant. Mechanisms underpinning host–parasite interactions are not clearly understood making well-informed strategies for control of the parasite difficult. To facilitate studies of Striga–host interactions for molecular and genetic studies, we: (i) established an efficient protocol for growing Striga from seeds in tissue culture; (ii) optimized protocols for its regeneration through direct organogenesis and somatic embryogenesis, and (iii) determined the effect of co-culturing host and parasite in the same culture media. We found the best auxin and cytokinin concentrations to be: 10.7 μM naphthaleneacetic acid (NAA) and 2.2 μM 6-benzylaminopurine (BAP) for embryogenic callus regeneration and 1.1–4.4 μM BAP without NAA for shoot multiplication. While seedling, stem and leaf explants induced callus with the same frequency, seed radicles did not produce any callus. Unexpectedly, we found that when Striga callus was added in rice growing on culture media, the parasite adversely affected the host through formation of lesions on leaves and resulted in less shoot induction from callus in the parasite. Techniques described in this study will enhance further understanding of Striga–host interactions. Highly efficient protocols for tissue culture of the obligate parasitic plant Striga hermonthica and detection of host phytotoxicity by the parasite on culture media.

Introduction Striga is a highly successful pathogen of cereal crops in sub-Saharan Africa. Also known as witchweed, Striga is an attractive parasitic plant whose beautiful flowers belie its noxiousness. Most cultivated cereals, including maize, millet, sorghum, and rice, are parasitized by at least one Striga species, leading to enormous economic losses. Control strategies are limited but include common agronomic practices of hand weeding, crop rotation, and general sanitization techniques. Striga-resistant crops, as well as tolerant ones, have also been used, but this resistance tends to break down with the emergence of new Striga variants. With limited and ineffective management options, Striga has continued to increase both its host range and area under infestation. In this article, we outline seven unique characteristics of Striga as a parasite of great economic importance, explore reasons for its success, and outline emerging control options.

Sorghum is a major food staple in sub-Saharan Africa (SSA), but its production is constrained by the parasitic plant Striga that attaches to the roots of many cereals crops and causes severe stunting and loss of yield. Away from cultivated farmland, wild sorghum accessions grow as weedy plants and have shown remarkable immunity to Striga. We sought to determine the extent of the resistance to Striga in wild sorghum plants. Our screening strategy involved controlled laboratory assays of rhizotrons, where we artificially infected sorghum with Striga, as well as field experiments at three sites, where we grew sorghum with a natural Striga infestation. We tested the resistance response of seven accessions of wild sorghum of the aethiopicum, drummondii, and arundinaceum races against N13, which is a cultivated Striga resistant landrace. The susceptible control was farmer-preferred variety, Ochuti. From the laboratory experiments, we found three wild sorghum accessions (WSA-1, WSE-1, and WSA-2) that had significantly higher resistance than N13. These accessions had the lowest Striga biomass and the fewest and smallest Striga attached to them. Further microscopic and histological analysis of attached Striga haustorium showed that wild sorghum accessions hindered the ingression of Striga haustorium into the host endodermis. In one of the resistant accessions (WSE-1), host and parasite interaction led to the accumulation of large amounts of secondary metabolites that formed a dark coloration at the interphase. Field experiments confirmed the laboratory screening experiments in that these same accessions were found to have resistance against Striga. In the field, wild sorghum had low Area under the Striga Number Progressive curve (AUSNPC), which measures emergence of Striga from a host over time. We concluded that wild sorghum accessions are an important reservoir for Striga resistance that could be used to expand the genetic basis of cultivated sorghum for resistance to the parasite.

The Association for Strengthening Agricultural Research in Eastern and Central Africa (ASARECA) through its Agrobiodiversity and Biotechnology Programme is enhancing the utilization of biotechnology research and development innovations in Eastern and Central Africa (ECA). We present successes in the application of biotechnology to enhance the productivity of cassava, sweet potato, banana, maize and sorghum in ECA. These products—drought tolerant maize, sorghum resistant to striga, as well as the technology for producing and distributing disease free planting materials of cassava, sweet potato and banana to farmers—are central for the agro-ecological intensification of farming systems in the central African highlands.