Abstract
Cassava, forming starch-rich, tuberous roots, is an important staple crop in smallholder farming systems in sub-Saharan Africa. Its relatively good tolerance to drought and nutrient-poor soils may be partly attributed to the crop’s association with arbuscular mycorrhiza fungi (AMF). Yet insights into AMF-community composition and richness of cassava, and knowledge of its environmental drivers are still limited. Here, we sampled 60 cassava fields across three major cassava-growing agro-ecological zones in Nigeria and used a DNA meta-barcoding approach to quantify large-scale spatial variation and evaluate the effects of soil characteristics and common agricultural practices on AMF community composition, richness and Shannon diversity. We identified 515 AMF operational taxonomic units (OTUs), dominated by Glomus, with large variation across agro-ecological zones, and with soil pH explaining most of the variation in AMF community composition. High levels of soil available phosphorus reduced OTU richness without affecting Shannon diversity. Long fallow periods (> 5 years) reduced AMF richness compared with short fallows, whereas both zero tillage and tractor tillage reduced AMF diversity compared with hoe tillage. This study reveals that the symbiotic relationship between cassava and AMF is strongly influenced by soil characteristics and agricultural management and that it is possible to adjust cassava cultivation practices to modify AMF diversity and community structure.Graphical abstract
Highlights
Cassava (Manihot esculenta) is a perennial woody shrub native to South America (Li and Zhu 2011; Okudoh et al 2014), forming tuberous roots rich in starch
Amplification of the 18S small subunit (SSU) ribosomal DNA (rDNA) region failed for eight cassava root samples, but a total of 4,390,014 sequences were successfully recovered from 232 root samples after Illumina sequencing
Our results show that cassava roots are highly colonized and that arbuscular mycorrhizal fungi (AMF) associated with cassava exhibit taxonomic differences at family and genus levels across different spatial scales
Summary
Cassava (Manihot esculenta) is a perennial woody shrub native to South America (Li and Zhu 2011; Okudoh et al 2014), forming tuberous roots rich in starch. Cassava has been labelled as the ‘drought, war and famine crop’ partly due to the crop’s ability to withstand drought (El-Sharkawy 2004). AMF (Glomeromycota) are root symbionts, commonly present in agricultural soils and associated with about 71% of all plant species (Brundrett and Tedersoo 2018). Apart from alleviating drought stress and nutrient deficiency in the host plant (Augé 2001; Birhane et al 2012; Ceballos et al 2013; Aliyu et al 2019) by forming a hyphal network extending widely through the soil (Bowles et al 2016), they are beneficial to overall soil quality (Rillig et al 2019) by contributing to soil aggregation (Barbosa et al 2019), via the release of glomalin (Liang et al 2015) and hyphae extension that entangles soil particles (Rillig et al 2015)
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
