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Abstract Detail

Crops and Wild Relatives

Crow, Taylor [1], Runcie, Daniel [1].

Characterizing a chromosomal inversion QTL in maize using RNA-seq.

Maize (Zea mays ssp. mays) was domesticated in lowland areas of southwest Mexico from the narrowly distributed teosinte, Zea mays ssp. parviglumus. Domestication of the species greatly altered the transcriptome of maize, especially in cis-regulatory regions. In Mexico, gene flow between maize and the highland subspecies of teosinte, Zea mays ssp. mexicana, purportedly facilitated the spread of maize into the relatively cool, dry highlands of Mexico. One region of the genome that introgressed from ssp. mexicana to maize was a chromosomal inversion on the long arm of chromosome 4, Inv4m. This genomic region was originally identified as a QTL in teosintes for leaf pigmentation and macrohairs, and was later shown to be an inversion distinguishing ssp. parviglumis from ssp. mexicana. Despite its association with adaptive phenotypes, little is known about the function of Inv4m.
Our goal in this study was to characterize the transcriptional reprogramming of Inv4m in response to highland conditions of Mexico. We used several parent donor lines to introgress Inv4m into the B73 reference genetic background, with 5 backcrosses to B73 to isolate the inversion into a common genetic background. We grew plants in growth chambers representing warm low elevation and cool high elevation environmental temperatures. We sampled 9 tissue types from plants at two different early developmental phases, and used RNA-seq and multivariate modeling to characterize the function of Inv4m in the maize genome.
We found that most genes within the inversion were differentially expressed compared to the genes in the colinear genomic region of B73. We found that Inv4m exhibited a moderate trans-regulatory effect in the B73 genetic background. We preformed gene set enrichment analysis and found variation in several gene categories which were consistent with highland adaptation.

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1 - UC Davis, Plant Sciences, 1 Shields Ave, Davis, California, 95616, United States

Chromosomal inversion.

Presentation Type: Oral Paper
Session: CWR1, Crops and Wild Relatives
Location: Tucson D/Starr Pass
Date: Wednesday, July 31st, 2019
Time: 10:30 AM
Number: CWR1010
Abstract ID:888
Candidate for Awards:None

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