Drought Tolerant Wheat Varieties Enrich Seed Microbiomes For Beneficial Microbes Under Drought Conditions

Climate change is predicted to increase the incidence and severity of drought conditions, posing a significant challenge for agriculture globally. Plant microbiomes have been demonstrated to aid crop species mitigate drought stress. In this study the wheat seed microbiomes from lines with contrasting drought tolerances were interrogated for microbes that alleviate drought stress. Metagenomic and culture-based methods were used to profile and characterise the seed microbiome composition of four drought tolerant and three drought susceptible wheat lines under rainfed and drought conditions. Curtobacterium flaccumfaciens ( Cf D3-25) and Arthrobacter sp. ( Ar sp. D4-14) were isolates enriched in drought tolerant lines under drought conditions and demonstrated the ability to promote wheat growth under drought conditions. Members of Triticeae inoculated with Cf D3-25 and Ar sp. D4-14 showed a biostimulation affect. This study indicates seed microbiomes from genetically distinct wheat lines enrich for beneficial bacteria in ways that are both line-specific and responsive to environmental stress. As such, seed from stress-phenotyped lines represents an invaluable resource for the identification of beneficial microbes with plant growth promoting activity that could improve commercial crop production, particularly under drought stress.