Can wild relatives of sorghum provide new sources of resistance or tolerance against Striga species?

Abstract

Summary The genus Striga contains some of the most noxious parasitic plants, which have a devastating impact on cereal production in Africa; of most importance are Striga hermonthica and Striga asiatica. Complete resistance to infection by Striga species does not exist in cultivated cereals. Of great interest is the possibility that wild relatives of cereals may provide a genetic basis for resistance or tolerance to infection and may be of enormous value for the development of resistant crops. A wild relative of cultivated sorghum, Sorghum arundinaceum, demonstrated tolerance to infection by S. asiatica, with little impact of S. asiatica on host growth or grain production compared with the detrimental impact of the parasite on cultivated sorghum. Infection by S.hermonthica, however, had a significant influence on host performance for both wild and cultivated sorghum. Differences in host:parasite responses may be explained by the timing of parasite attachment and differences in host specificity for these two Striga species.

The Strigolactone Germination Stimulants of the Plant-ParasiticStrigaandOrobanchespp. Are Derived from the Carotenoid Pathway

“…Plants were grown in autoclaved perlite in separate tubes or in 1-L pots (15-cm diameter) (Gurney et al, 2002). Small seedlings were transferred to glass tubes to grow hydroponically in a phytotron 14/10-h photoperiod at 250 mmol photonsÁm 22 Ás 21 at 28/23°C.…”

Genetic structure and relationships within and between cultivated and wild sorghum (Sorghum bicolor (L.) Moench) in Kenya as revealed by microsatellite markers

“…Wild relatives of sorghum are recognised as broad genetic base reservoirs and potential sources for resistance and adaptation traits in breeding programs (Gurney et al 2002;Kamala et al 2002;Reed et al 2002;Rao Kameswara et al 2003;Rich et al 2004) and deserve special conservation attention.…”

Striga

“…For these poor farmers, millets are the major staple food providing them with carbohydrates and is the main source of vitamins and minerals including zinc and iron, (Andrews and Kumar, 1992;Rai et al, 2012;Bangoura et al, 2011;Mannuramath et al, 2015;Mishra et al, 2014). Hence, yield losses lead to significant negative socioeconomic problems: Striga affects the life of more than 300 million people in Africa and causes economic damage equivalent or even more than US$10 billion annually (Obilana and Ramaiah, 1992;Gurney et al, 2002;Rodenburg et al, 2005;Ejeta, 2007;Scholes and Press, 2008;Westwood et al, 2012). More recently, as a consequence, sub-Saharan Africa has been reported to be the region with the highest prevalence of poverty and undernourishment, with one in four people (24.8%) estimated to be hungry (FAO, IFAD and WFP, 2013).…”

“…More recently, new sorghum genotypes have been reported to be resistant to Striga (Robert, 2011). Resistance to Striga has been also documented to be present in wild accessions of Sorghum versicolor, Sorghum drummondii and Sorghum arundinaceum (Lane et al, 1995;Gurney et al, 2002).…”

“…Millets thus play a critical role in ensuring food security in these regions Senthilvel et al, 2008 (Gurney et al, 2003(Gurney et al, , 2006Elzein and Kroschel, 2004;Vasey et al, 2005;Amusan et al, 2008). Indeed, Striga are the major and persistent biotic threat to production of these crops mostly grown on the hottest and driest marginal regions of sub-Saharan Africa, Middle East and large part of Asia (Gurney et al, 2002;Gressel et al, 2004;Ejeta, 2007;Rispail et al, 2007;Scholes and Press, 2008;Parker, 2012). At present, over 50 million ha of the arable farmland under cereals in sub-Saharan Africa are infested by Striga.…”