Diversity and functional potential of the Sorghum Root Microbiome to control: Striga hermonthica

Sorghum (Sorghum bicolor) is a major cereal crop that millions of subsistence farmers in Sub-Saharan Africa (SSA) rely on. However, the scourging impact of the root parasitic weed Striga (Striga hermonthica, a.k.a. “witch-weed”) has remained a major constraint hampering the productivity of sorghum in SSA. Several Striga management practices were developed and implemented, including resistance breeding, herbicides, and improved farm management practices. Unfortunately, the unavailability of eradication systems made the Striga problem to persist as a threat to food security in SSA. The plant microbiome is known to alleviate hosts from biotic and abiotic stresses. Therefore, identification and applications of potential microbes against Striga will be vital towards the development of sustainable control strategies. In this PhD thesis, the diversity, functional attributes, and biosynthetic potential of sorghum root microbiome was deciphered and their effectiveness against Striga development was determined. Despite the immense influence of host related and edaphic factors, distinct sorghum cultivars recruit and assemble a set of common ‘core’ microbes with shared functionalities known to benefit host plants. The core microbes significantly suppressed Striga seed germination and viability. Volatile organic compounds (VOCs) produced by the core microbes were significantly correlated with the higher suppression and poor viability rate. This study also generated detailed information regarding the sorghum microbiome, metabolome, and the impact of Striga thereof. In conclusion, the results of this thesis research will be instrumental in the design of microbial-based effective, affordable, and sustainable strategy to control Striga that seamlessly integrates into the ongoing management systems. <br>