Development of root phenotyping platforms for identification of root architecture mutations in EMS-induced and Low-path-sequenced Sorghum mutant population

Authors: TISHCHENKO, VIKTOR - University Of Georgia; Wang, Ming; Xin, Zhanguo; Harrison, Melanie

Submitted to: American Journal of Plant Sciences
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/2/2020
Publication Date: 6/28/2020
Citation: Tishchenko, V., Wang, M.L., Xin, Z., Harrison, M.L. 2020. Development of root phenotyping platforms for identification of root architecture mutations in EMS-induced and Low-path-sequenced Sorghum mutant population. American Journal of Plant Sciences. 11:838-850. https://doi.org/10.4236/ajps.2020.116060.
DOI: https://doi.org/10.4236/ajps.2020.116060

Interpretive Summary: Sorghum is an important grain crop that is particularly valuable for its ability to withstand various environmental stresses. Variations in root growth are in part responsible for this ability to adapt to harsh environments. By observing the different root traits and their association with stress, much can be learned on how certain sorghum types are more adapted to handle these stresses. Unfortunately, observation of root traits is difficult and methods to rapidly screen a large set of individual plants for root traits in sorghum is limited. In this study, we investigate different methods to observe and characterize root traits in sorghum under various soil phosphorus levels and discuss the pros and cons of each method tested.

Technical Abstract: Sorghum’s natural adaptation to a wide range of abiotic stresses provides diverse genetic reserves for potential improvement in crop stress tolerance. Growing interest in sorghum research has led to the expansion of genetic resources though establishment of the sorghum association panel (SAP), generation of mutagenized populations, and recombinant inbred line (RIL) populations etc. Despite rapid improvement in biotechnological tools, lack of efficient phenotyping platforms remains one of the major obstacles in utilizing these genetic resources. Scarcity of efforts in root system phenotyping hinders identification and integration of the superior root traits advantageous to stress tolerance. Here, we explored multiple approaches in root phenotyping of an ethyl methanesulfonate (EMS)-mutagenized sorghum population. Paper-based growth pouches (PGP) and hydroponics were employed to analyze root system architecture (RSA) variations induced by mutations and to test root development flexibility in response to phosphorus deficiency in early growing stages. Preliminary observation revealed distinct phenotypic variations which were qualitatively and quantitatively systemized for association analysis. Phenotypes/ideotypes with root architecture variations potentially correlated with Pi acquisition were selected to evaluate their contribution to P-efficiency (PE). Sand mixed with P-loaded activated alumina substrate (SAS) provided closely to natural but still controlled single-variable conditions with regulated Pi availability. We propose here SAS to be used for evaluating selected sorghum candidates for PE. The ability of rapidly screening root phenotypes holds great potential for discovering genes responsible for relevant root traits and utilizing mutations to improve nutrient efficiency and crop productivity.