HY5 is not integral to light mediated stomatal development in Arabidopsis

Abstract

Light is a crucial signal that regulates many aspects of plant physiology and growth including the development of stomata, the pores in the epidermal surface of the leaf. Light signals positively regulate stomatal development leading to changes in stomatal density and stomatal index (SI; the proportion of cells in the epidermis that are stomata). Both phytochrome and cryptochrome photoreceptors are required to regulate stomatal development in response to light. The transcription factor ELONGATED HYPOCOTYL 5 (HY5) is a key regulator of light signalling, acting downstream of photoreceptors. We hypothesised that HY5 could regulate stomatal development in response to light signals due to the putative presence of HY5 binding sites in the promoter of the STOMAGEN (STOM) gene, which encodes a peptide regulator of stomatal development. Our analysis shows that HY5 does have the potential to regulate the STOM promoter in vitro and that HY5 is expressed in both the epidermis and mesophyll. However, analysis of hy5 and hy5 hyh double mutants (HYH; HY5-HOMOLOG), found that they had normal stomatal development under different light conditions and the expression of stomatal developmental genes was not perturbed following light shift experiments. Analysis of stable lines overexpressing HY5 also showed no change in stomatal development or the expression of stomatal developmental genes. We therefore conclude that whilst HY5 has the potential to regulate the expression of STOM, it does not have a major role in regulating stomatal development in response to light signals.

Machine learning enabled phenotyping for GWAS and TWAS of WUE traits in 869 field-grown sorghum accessions

“…Putative SD candidates in this gene set included a cell wall expansion-type protein ( EXPB2 (Marowa et al, 2016), an ABA-sensitive MAP KINASE ( RAF10 (Lee et al, 2015)), the PAP10 purple acid phosphatase (Hepworth et al, 2016), and an asparagine-rich protein ( NRP ) that is documented to positively regulate the expression of CRY2 (Zhou et al, 2017), a blue light receptor which in turn increases stomatal index (Kang et al, 2009) (Figure 6, Table S9). Further genes with known roles in stomatal development identified via alternative mapping approaches included AMP1 (Shi et al, 2013; López-García et al, 2020), ATE1 (Movahedi, 2013; Vicente et al, 2019), and TED5 (Tossi et al, 2014; Zoulias et al, 2020). Additionally, through mapping for SD we identified multiple genes with putative and known roles in stomatal behavior, e.g.…”

Karrikins control seedling photomorphogenesis and anthocyanin biosynthesis through a HY5‐BBX transcriptional module

“…, 2014; Zoulias et al. , 2020). The bbx21‐2 (GT_5_101627) mutant originates from Arabidopsis Ler accession and was described previously (Datta et al.…”

Pest management via endophytic colonization of tobacco seedlings by the insect fungal pathogen Beauveria bassiana

“…The number of stomata and epidermal cells were counted using Photoshop CS6 software. Stomatal density (stomata per mm 2 leaf area) and the stomatal index ( I ) was calculated using the formula: 35 in which S and E indicate the number of stomata and epidermal cells in a given leaf area, respectively. Experiments were repeated three times.…”