Enhanced Utilization of Biotechnology Research and Development Innovations in Eastern and Central Africa for Agro-ecological Intensification

Masiga, Clet Wandui; Mugoya, Charles; Ali, Rasha; Mohamed, Abdalla I.; Osama, Sarah; Ngugi, Abigail J.; Kiambi, D.; Villiers, Santie de; Ngugi, Kahiu; Machuka, Jesse; Oduor, Richard; Runo, Steven; Adam, Rasha; Matheka, Jonathan; Bedada, Leta Tulu; Seth, Miccah Songelael; Kuria, Eric Kimani; Ndirigwe, J.; Muthamia, Zachary Kithinji; Nasona, Bouwe; Ntimpirangeza, Michel; Tsegaye, Engida; Nyamongo, D. O.; Ogero, Kwame; Mburugu, Gitonga; Mukasa, Settumba B.; Kim, Dong-Jin; Ferguson, Morag; Mneney, Emmarold E.; Nsubuga, E.N.B.; Rishurimuhirwa, Theodomir; Byamugisha, Donald; Wamatsembe, Isaac; Nzuki, Inosters; Mkamilo, Geoffrey; Kimata, Bernadetta; Ketema, Seyfu

doi:10.1007/978-3-319-07662-1_8

Cited by 5 publications

(4 citation statements)

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“…This form of resistance, which is exemplified by N13, has led to identification of several Quantitative Trail Loci (QTL) by mapping populations of resistant N13 and susceptible E103 (Haussmann et al, 2004 ). These QTL have been integrated into breeding programmes in Africa (Masiga et al, 2014 ; Mohamed et al, 2014 ; Yohannes et al, 2015 ). Therefore, for quantitative Striga resistance comparable to N13, WSE-1, WSA-1, and WSA-2 are good candidate accessions that could be integrated into varieties preferred by farmers.…”

Section: Discussionmentioning

confidence: 99%

Novel Sources of Witchweed (Striga) Resistance from Wild Sorghum Accessions

et al. 2017

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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.

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Section: Discussionmentioning

confidence: 99%

Novel Sources of Witchweed (Striga) Resistance from Wild Sorghum Accessions

et al. 2017

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“…Infection can occur in resistant cultivars such as Kaleso and Namikonga, but multiplication, movement, and disease symptoms are limited (Kaweesi et al, 2014). Tolerant cultivars Nachinyaya and Kiroba can be infected and support virus movement and replication, but with intermediate symptoms, while susceptible cassava cultivars 60444 and Albert support high levels of virus concentration and develop severe CBSD symptoms (Hillocks et al, 2001;Maruthi et al, 2014;Masiga et al, 2014;Ogwok et al, 2015). Since symptoms may be subtle or develop only within the underground storage roots, CBSD may claim an entire crop without the farmer's knowledge until harvest Patil et al, 2015).…”

Section: Introductionmentioning

confidence: 99%

Simultaneous CRISPR/Cas9‐mediated editing of cassava eIF4E isoforms nCBP‐1 and nCBP‐2 reduces cassava brown streak disease symptom severity and incidence

Gomez

Lin

Moll

et al. 2018

Plant Biotechnology Journal

283

148

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Cassava brown streak disease (CBSD) is a major constraint on cassava yields in East and Central Africa and threatens production in West Africa. CBSD is caused by two species of positive-sense RNA viruses belonging to the family Potyviridae, genus Ipomovirus: Cassava brown streak virus (CBSV) and Ugandan cassava brown streak virus (UCBSV). Diseases caused by the family Potyviridae require the interaction of viral genome-linked protein (VPg) and host eukaryotic translation initiation factor 4E (eIF4E) isoforms. Cassava encodes five eIF4E proteins: eIF4E, eIF(iso)4E-1, eIF(iso)4E-2, novel cap-binding protein-1 (nCBP-1), and nCBP-2. Protein-protein interaction experiments consistently found that VPg proteins associate with cassava nCBPs. CRISPR/Cas9-mediated genome editing was employed to generate ncbp-1, ncbp-2, and ncbp-1/ncbp-2 mutants in cassava cultivar 60444. Challenge with CBSV showed that ncbp-1/ncbp-2 mutants displayed delayed and attenuated CBSD aerial symptoms, as well as reduced severity and incidence of storage root necrosis. Suppressed disease symptoms were correlated with reduced virus titre in storage roots relative to wild-type controls. Our results demonstrate the ability to modify multiple genes simultaneously in cassava to achieve tolerance to CBSD. Future studies will investigate the contribution of remaining eIF4E isoforms on CBSD and translate this knowledge into an optimized strategy for protecting cassava from disease.

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“…In line with this assertion, Striga resistance quantitative trail loci (QTL) has been identified in sorghum (Haussmann et al, 2004) and rice (Swarbrick et al, 2009) in a Recombinant Inbred Line (RIL) population that was derived from a cross between the resistant cultivar N13 and a susceptible cultivar E36-1 (Haussmann et al, 2004). Such QTLs have been further utilised in breeding programs in Africa (Masiga et al, 2014;Yohannes et al, 2015). The biological and genetic mechanisms underpinning this form of resistance in Striga are not yet understood but it is reasonable to assume that the effect is a result of multiple genes acting to fortify the host against invasion by the parasite.…”

Section: Exploiting Host Resistance As a Control Strategy Against Strigamentioning

confidence: 96%

Modern Breeding Approaches for Durable Resistance Against the Parasitic Plant Striga

Runo¹

2019

AFOC

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Crop losses caused by parasitic plants of the genus Striga pose a great danger to the livelihoods of millions of smallholder farmers in Africa. The parasite attaches to host crops and siphons nutrients leading to severe retardation and crop death. Controlling Striga is difficult because of the parasite’s ability to produce large amounts of seeds that can remain dormant in the soil for decades – only germinating in response to chemical cues (strigolactones) from the host. In recent years, breeding crops for host-based resistance has been prioritized. However, such programs have not taken into account Striga’s ability to overcome host resistance. As a result, introduced resistance fails because of increased Striga virulence (infection severity). This article reviews technologies for a new paradigm in Striga resistance breeding that incorporates host resistance breeding with well-informed knowledge of parasite resistance in order to ensure durability of resistance.

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Enhanced Utilization of Biotechnology Research and Development Innovations in Eastern and Central Africa for Agro-ecological Intensification

Cited by 5 publications

References 3 publications

Novel Sources of Witchweed (Striga) Resistance from Wild Sorghum Accessions

Novel Sources of Witchweed (Striga) Resistance from Wild Sorghum Accessions

Simultaneous CRISPR/Cas9‐mediated editing of cassava eIF4E isoforms nCBP‐1 and nCBP‐2 reduces cassava brown streak disease symptom severity and incidence

Modern Breeding Approaches for Durable Resistance Against the Parasitic Plant Striga

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