TITLE:
Development of Root Phenotyping Platforms for Identification of Root Architecture Mutations in EMS-Induced and Low-Path-Sequenced Sorghum Mutant Population
AUTHORS:
Viktor Tishchenko, Mingli Wang, Zhanguo Xin, Melanie Harrison
KEYWORDS:
Sorghum, Mutagenized, Phenotyping, Root System Architecture, P Efficiency and Deficiency, Nutrients
JOURNAL NAME:
American Journal of Plant Sciences,
Vol.11 No.6,
June
28,
2020
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. PGP
method had improved capabilities compared to hydroponics providing inexpensive,
space-saving, and high-throughput phenotyping of sorghum roots. 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. Due
to higher labor and cost input we propose 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.