The maize d2003, a novel allele of VP8, is required for maize internode elongation

Abstract

The d2003 is a natural dwarf mutant from maize inbred line K36 and has less than one-third of K36 plant height with severely shortened internodes. In this study, we reported the cloning of d2003 gene using positional cloning. The results showed that there was a single-base insertion in the coding region of Viviparous8 (VP8) in d2003 mutant, which resulted in a premature stop codon. Further genetic allelism tests confirmed that d2003 mutation is a novel allele of VP8. VP8 is mainly expressed in the stem apex, young leaves, and developing vascular tissues, and its expression levels in nodes are significantly higher than that in internodes at 12-leaf stage. Subcellular localization demonstrated that the VP8 protein is localized to the endoplasmic reticulum and the N-terminal 26 amino acids (aa) of VP8 protein are essential to its localization in ER. Further transgenic experiments showed that lack of the 26 aa leads to loss of VP8 function in Arabidopsis amp1 phenotype rescue. These results strongly suggested that the N-terminal 26 aa is critical for VP8 protein localization, and the correct protein localization of VP8 in ER is necessary for its function.

Analysis of differential expression of genes induced by ethephon in elongating internodes of maize plants

“…These genes, preferentially expressed in response to internal and external stimuli, can trigger a wide range of developmental processes in plants. For example, Zm.5799.1.A1_at upregulation enhances antioxidants in maize [45] , implying that these are excellent candidates for involvement in the biosynthetic processes and cellular organization of internodes.…”

ALTERED MERISTEM PROGRAM1Suppresses Ectopic Stem Cell Niche Formation in the Shoot Apical Meristem in a Largely Cytokinin-Independent Manner

“…In contrast to other mutants with deregulated shoot meristem activity, amp1 SAM size normalizes after floral transition, and altered shoot meristem activity appears to be limited to decreased apical dominance (Vidaurre et al, 2007). Mutants of AMP1 orthologs in Zea mays, rice (Oryza sativa), and Lotus japonicus generate comparable SAM defects, indicating that the function of this factor in respect to shoot development is conserved among higher plants (Suzuki et al, 2008;Kawakatsu et al, 2009;Suzaki et al, 2013;Lv et al, 2014).…”

Unoccupied aerial system enabled functional modeling of maize (Zea mays L.) height reveals dynamic expression of loci associated to temporal growth

“…ZmMADS69 has higher expression levels in temperate compared to tropical germplasm, leading to significant detection in temperate by tropical crosses [52], such as LH82xLAMA among others [23, 24, 53]. The identified region on chromosome 1 contained the viviparous8 (vp8; GRMZM2G010353; Chr1: 286390345..286398537) locus which exhibits dwarfism due to reduced cell proliferation [54]. Both loci may be deterministic QTL (dQTL) because the differential allelic variation affected the whole growth process [55] and was unaffected by environmental stimuli; ZmMADS69 effect was not influenced by day length [52] and vp8 exhibited normal plant hormone response [54].…”

“…The identified region on chromosome 1 contained the viviparous8 (vp8; GRMZM2G010353; Chr1: 286390345..286398537) locus which exhibits dwarfism due to reduced cell proliferation [54]. Both loci may be deterministic QTL (dQTL) because the differential allelic variation affected the whole growth process [55] and was unaffected by environmental stimuli; ZmMADS69 effect was not influenced by day length [52] and vp8 exhibited normal plant hormone response [54]. These results coupled with basic biological understanding indicated that allelic changes in loci can have a fundamental impacts on the functional growth trajectory of maize, in contrast to the small shift in phenotypic expression of a single trait It is therefore understandable that these two “major genes” have been previously identified and described in multiple studies, while the smaller and ephemeral effect loci are mostly unknown.…”