Abstract Detail

Comparative Genomics/Transcriptomics

Deb, Sontosh [1], Adhikari, Bishnu [2], Hofford, Nathaniel [2], MacNeill, Bryan [2], Motley, M'Kayla [2], McKain, Michael [3].

Evolution of flooding tolerance in maize relatives.

Maize (Zea mays L.) is an economically valuable crop grown widely across the world. Maize issensitive to soil flooding and submergence/waterlogging leading to yield loss and potential death of the plant. Variation in precipitation patterns and increased flooding due to climate change may result in lower overall maize productivity in afflicted areas. Since maize is one of the world’s most planted crops and a staple for millions, it is vital to develop improved varieties of maize to cope with the increasing occurrence of flooding stress. Maize is an ancient allopolyploid and shares this event with other members of the genera Zea and Tripsacum. Recently, Vossia cuspidata (Roxb.) Griff. (hippo grass) was identified as a putative, extant relative of one of Zea/Tripsacum’s diploid progenitors. The parental relative Vossia cuspidata and close relatives Zea nicaraguensis H.H.Itis and B.F. Benz and Tripsacum dactyloides L.show increased tolerance to submergence/waterlogging stress compared to cultivated maize. Several flood tolerant quantitative trait loci have been identified in maize inbred lines suggesting maize may have the capacity for flooding-tolerance. This study explores the evolution of flooding tolerance in maize and its relatives by comparing expression patterns and paralog usage in taxa that share the same allopolyploid event (Z. mays, Z. nicaraguensis, and T. dactyloides) versus a putative parent relative (V. cuspidata). Using a flooding-sensitive inbred maize line (B73), two flooding-tolerant relatives Z. nicaraguensis and T. dactyloides, and one flooding-tolerant, parental relative V. cuspidata, we can dissect the influence of a lineage with known flooding tolerance as a parent in an allopolyploidy event on the evolution of flooding tolerance in taxa that share the same subgenomic history. Individuals at the six-leaf stage were subject to flooding conditions by maintaining 2-3 cm water layer above the substrate of their pots. Leaf and root samples were collected before the waterlogging treatment (0h), after four hours, and after 72 hours to represent short and long term stressed conditions. Differential expression analysis were conducted across all taxa, tissues, and treatments while considering the evolutionary history of the genes (i.e. the subgenome of origin) when possible. Root tissue was collected from each replicate sampled for transcriptomes for microscopic analysis. We investigated the variation in aerenchyma formation across the 72-hour flooding treatment to link anatomical changes to expression changes. This work allows us to identify differential expression patterns associated with subgenomic-specific responses to flooding and to identify potential targets in the maize genome that could be used to improve flooding tolerance in maize lines. The identification of flooding tolerance genes will potentially help to develop flooding-tolerant cultivars, while the comparison of a crop to wild relatives demonstrates the need for crop scientists to look to nature for solutions to agricultural problems.

1 - The University of Alabama, 405 Mary Harmon Bryant Hall, Tuscaloosa, AL, 35487, United States
2 - The University of Alabama, Department of Biological Sciences, 410 Mary Harmon Bryant Hall, Tuscaloosa, AL, 35487, USA
3 - University Of Alabama, 411 Mary Harmon Bryant Hall, Tuscaloosa, AL, 35487, United States

climate change
gene expression
Root anatomy
Wild relatives

Presentation Type: Poster
Number: PGT007
Abstract ID:886
Candidate for Awards:None

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