Comparative transcriptomes between viviparous1 and wildtype maize developing endosperms in response to water deficit

• We analyzed transcriptomes of maize endosperms under water deficit.
• We compared global gene expression between vp1 and wildtype endosperms.
• We found 164 and 122 transcripts were affected by water deficit in wildtype and vp1 endosperms, respectively.
• The Vp1 gene plays a role in regulating transcript expression in maize endosperm development in response to water deficit, and this regulation is likely modulated via ABA signaling pathway.

Maize kernel development is particularly sensitive to water stress at the early post-pollination phase. Endosperm plays an essential role in support of embryo development and represents the bulk of carbohydrate storage in the kernel. In the present study, we compared transcriptomes of developing maize endosperms between an ABA-insensitive mutant, viviparous1 (vp1), and wild type (wt) under water deficit. A total of 122 and 164 transcripts were significantly affected by water deficit in vp1 and wt, respectively. Transcript profiles indicated that the Vp1 transcription factor contributed to regulation in response to water stress at early stages of maize endosperm development. Genes involved in transcriptional regulation and signal transduction were particularly dependent on presence of a functional Vp1 allele, as 83% the stress-affected genes in these categories were up-regulated by water stress in the wt, but only 34% were up-regulated in the mutant. This suggests that the loss of ABA sensitivity altered signaling networks in response to water deficit such that the mutant was unable to up-regulate the expression of many genes that normally play regulatory roles. Thus, the Vp1 gene plays a role in regulating transcript expression in maize endosperm development in response to water deficit, and this regulation is likely modulated via ABA signaling pathway.