Differentiated transcriptional signatures in the maize landraces of Chiapas, Mexico
Periodo de realización: 1900/01/01 al 2017/01/01
Tipo: Artículo científico
Lugar(es) de estudio: Frontera Comalapa, Chis., México, La Trinitaria, Chis., México, San Cristóbal de las Casas, Chis., México
Resumen: "Background: Landrace farmers are the keepers of crops locally adapted to the environments where they are cultivated.
Patterns of diversity across the genome can provide signals of past evolution in the face of abiotic and biotic change.
Understanding this rich genetic resource is imperative especially since diversity can provide agricultural security as
climate continues to shift.
Results: Here we employ RNA sequencing (RNA-seq) to understand the role that conditions that vary across a landscape
may have played in shaping genetic diversity in the maize landraces of Chiapas, Mexico. We collected landraces from
three distinct elevational zones and planted them in a midland common garden. Early season leaf tissue was collected
for RNA-seq and we performed weighted gene co-expression network analysis (WGCNA). We then used association
analysis between landrace co-expression module expression values and environmental parameters of landrace origin to
elucidate genes and gene networks potentially shaped by environmental factors along our study gradient. Elevation of
landrace origin affected the transcriptome profiles. Two co-expression modules were highly correlated with temperature
parameters of landrace origin and queries into their ‘hub’ genes suggested that temperature may have led to
differentiation among landraces in hormone biosynthesis/signaling and abiotic and biotic stress responses. We
identified several ‘hub’ transcription factors and kinases as candidates for the regulation of these responses.
Conclusions: These findings indicate that natural selection may influence the transcriptomes of crop landraces along
an elevational gradient in a major diversity center, and provide a foundation for exploring the genetic basis of local
adaptation. While we cannot rule out the role of neutral evolutionary forces in the patterns we have identified,
combining whole transcriptome sequencing technologies, established bioinformatics techniques, and common
garden experimentation can powerfully elucidate structure of adaptive diversity across a varied landscape.
Ultimately, gaining such understanding can facilitate the conservation and strategic utilization of crop genetic
diversity in a time of climate change."