Small auxin upregulated RNA (SAUR) gene family in maize: Identification, evolution, and its phylogenetic comparison with Arabidopsis, rice, and sorghum

Abstract

Small auxin-up RNAs (SAURs) are the early auxin-responsive genes represented by a large multigene family in plants. Here, we identified 79 SAUR gene family members from maize (Zea mays subsp. mays) by a reiterative database search and manual annotation. Phylogenetic analysis indicated that the SAUR proteins from Arabidopsis, rice, sorghum, and maize had divided into 16 groups. These genes were non-randomly distributed across the maize chromosomes, and segmental duplication and tandem duplication contributed to the expansion of the maize SAUR gene family. Synteny analysis established orthology relationships and functional linkages between SAUR genes in maize and sorghum genomes. We also found that the auxin-responsive elements were conserved in the upstream sequences of maize SAUR members. Selection analyses identified some significant site-specific constraints acted on most SAUR paralogs. Expression profiles based on microarray data have provided insights into the possible functional divergence among members of the SAUR gene family. Quantitative real-time PCR analysis indicated that some of the 10 randomly selected ZmSAUR genes could be induced at least in maize shoot or root tissue tested. The results reveal a comprehensive overview of the maize SAUR gene family and may pave the way for deciphering their function during plant development.

SAUR Proteins as Effectors of Hormonal and Environmental Signals in Plant Growth

“…Genomic bioinformatic analyses have revealed that there are 81 SAURs (including two pseudogenes) in Arabidopsis (Hagen and Guilfoyle, 2002), 58 SAURs (including two pseudogenes) in rice (Jain et al, 2006), 18 SAURs in moss (Rensing et al, 2008), 71 SAURs in sorghum (Wang et al, 2010), 134 SAURs in potato (Wu et al, 2012), 99 SAURs in tomato (Wu et al, 2012), and 79 SAURs in maize (Chen et al, 2014). Typically, SAUR genes are not randomly distributed in the genome, as many of them are found in tandem arrays of extremely highly related genes in soybean (McClure et al, 1989), Arabidopsis (Hagen and Guilfoyle, 2002), rice (Jain et al, 2006), tomato (Wu et al, 2012), and maize (Chen et al, 2014). Tandem and segmental duplication events likely contributed to the expansion of the SAUR gene family (Wu et al, 2012; Chen et al, 2014).…”

“…Typically, SAUR genes are not randomly distributed in the genome, as many of them are found in tandem arrays of extremely highly related genes in soybean (McClure et al, 1989), Arabidopsis (Hagen and Guilfoyle, 2002), rice (Jain et al, 2006), tomato (Wu et al, 2012), and maize (Chen et al, 2014). Tandem and segmental duplication events likely contributed to the expansion of the SAUR gene family (Wu et al, 2012; Chen et al, 2014). The genomic structures of SAUR genes show similar features.…”

Proton pump and plant cell elongation

“…Since the early 2000s, data on the enzyme hormone-dependent C-terminal domain phosphorylation has been accumulating (Palmgren, 2001;Takahashi, Hayashi, and Kinoshita, 2012;Chen, Hao, and Cao, 2014). It was shown that gibberellic acid enhances the phosphorylation of Thr-947, and cytokinin, on the contrary, reduces this process (Chen, Hao, and Cao, 2014).…”

“…It was shown that gibberellic acid enhances the phosphorylation of Thr-947, and cytokinin, on the contrary, reduces this process (Chen, Hao, and Cao, 2014). The binding of brassinosteroids to the BRI1 receptor resulted in rapid hyperpolarization (Caesar et al, 2011).…”

“…Detailed analysis of the event is still in progress, but some data indicate the possibility of direct interaction of the receptor kinase BRI1 with AHA1. In contrast, abscisic acid (ABA), known to inhibit elongation, dramatically reduces the level of H + -ATPase phosphorylation after addition to guard cells (Hayashi, Inoue, Takahashi, Kinoshita, 2011;Chen, Hao, Cao, 2014). Similarly, in hypocotyls ABA decreases phosphorylation of Thr-947, depending on ABI1 phosphatase (ABA signaling proteins phosphatases 2C, Hayashi, Takahashi, Inoue, and Kinoshita, 2014).…”