Transcriptome Profiling of Leaf Elongation Zone under Drought in Contrasting Rice Cultivars

<div><p>Inhibition of leaf elongation and expansion is one of the earliest responses of rice to water deficit. Despite this sensitivity, a great deal of genetic variation exists in the extant of leaf elongation rate (LER) reduction in response to declining soil moisture. We analyzed global gene expression in the leaf elongation zone under drought in two rice cultivars with disparate LER sensitivities to water stress. We found little overlap in gene regulation between the two varieties under moderate drought; however, the transcriptional response to severe drought was more conserved. In response to moderate drought, we found several genes related to secondary cell wall deposition that were down regulated in Moroberekan, an LER tolerant variety, but up-regulated in LER sensitive variety IR64.</p> </div

Relative leaf elongation under soil drying.

<p>Bars represent +/- SE.</p

Number of differentially expressed genes for each condition at FDR 0.1 and 0.01.

<p>Number of differentially expressed genes for each condition at FDR 0.1 and 0.01.</p

Overlap of DEGs between IR64 and Moroberekan.

<p>A. Up-regulated FTSW 1-0.5 B. Up-regulated FTSW 0.5-0.2 C. Down-regulated FTSW 1-0.5 D.Down-regulated FTSW 0.5-0.2. The area of circles and their overlap is proportional to the number of genes represented.</p

Expression level polymorphisms for each condition at FDR 0.1 and 0.01.

<p>Expression level polymorphisms for each condition at FDR 0.1 and 0.01.</p

Genotypic differentiation of transcriptome response to moderate and severe soil drying.

<p>Fold change of all genes for IR64 (x- axis) and Moroberekan (y-axis) from FTSW 1-0.5 (panel A, r² = −0.22) and FTSW 0.5-0.2 (panel B, r^2 =0.63).</p

Cell Wall DEGs.

<p>Fold change difference for all cell wall annotated genes with at least two-fold change under mild stress in both IR64 (solid bars) and Moroberekan (striped bars).</p

Seed and plant traits for the plant materials used.

<p>Seed and plant traits for the plant materials used.</p

Number of single nucleotide polymorphisms (SNPs) in the introgression regions.

<p>Number of single nucleotide polymorphisms (SNPs) in the introgression regions.</p

Summary of the sequencing data and plant materials.

<p>Summary of the sequencing data and plant materials.</p