PhDHS Is Involved in Chloroplast Development in Petunia

Abstract

Deoxyhypusine synthase (DHS) is encoded by a nuclear gene and is the key enzyme involved in the post-translational activation of the eukaryotic translation initiation factor eIF5A. DHS plays important roles in plant growth and development. To gain a better understanding of DHS, the petunia (Petunia hybrida) PhDHS gene was isolated, and the role of PhDHS in plant growth was analyzed. PhDHS protein was localized to the nucleus and cytoplasm. Virus-mediated PhDHS silencing caused a sectored chlorotic leaf phenotype. Chlorophyll levels and photosystem II activity were reduced, and chloroplast development was abnormal in PhDHS-silenced leaves. In addition, PhDHS silencing resulted in extended leaf longevity and thick leaves. A proteome assay revealed that 308 proteins are upregulated and 266 proteins are downregulated in PhDHS-silenced plants compared with control, among the latter, 21 proteins of photosystem I and photosystem II and 12 thylakoid (thylakoid lumen and thylakoid membrane) proteins. In addition, the mRNA level of PheIF5A-1 significantly decreased in PhDHS-silenced plants, while that of another three PheIF5As were not significantly affected in PhDHS-silenced plants. Thus, silencing of PhDHS affects photosynthesis presumably as an indirect effect due to reduced expression of PheIF5A-1 in petunia.Significance: PhDHS-silenced plants develop yellow leaves and exhibit a reduced level of photosynthetic pigment in mesophyll cells. In addition, arrested development of chloroplasts is observed in the yellow leaves.

PaACL silencing accelerates flower senescence and changes the proteome to maintain metabolic homeostasis in Petunia hybrida

“…Western blot analyses were performed according to the methods of Liu et al (2019) . The peptides ( Supplementary Table S4 ) expressed in Escherichia coli of three proteins, PamCS (Peaxi162Scf00402g00612.1), PaPDC2 (pyruvate decarboxylase-2, Peaxi162Scf00014g00030.1) and PaGELP (GDSL, esterase/lipase, Peaxi162Scf00038g01135.1), and the synthetic acetylation peptides (QQFNKacKMNS) of the protein PaGELP255Kac, were used as antigens for antibody production in rabbits from Diaan ( http://www.dia-an.cn/ ).…”

Hypusination, a Metabolic Posttranslational Modification of eIF5A in Plants during Development and Environmental Stress Responses

“…Evidence shows that the expression of DHS could spatially and temporally change via the developmental stages. In Petunia, suppression of DHS caused abnormal chloroplast development in the leaves and delayed leaf senescence [ 32 ]. However, in Arabidopsis, the leaf-specific suppression of DHS resulted in growth enhancement without any negative pleiotropic effects [ 33 ] despite an earlier study that demonstrated the pleiotropic effects of suppressed DHS expression in the same plants [ 4 ].…”

“…Suppressed DHS caused increased root biomass, bigger leaves, and enhanced seed yield in Arabidopsis during drought stress [ 4 ]. Sectored chlorotic leaves were also detected in Petunia plants, suggesting that PhDHS is involved in their chloroplast development [ 32 ], indicating a functional difference between different plant species. DHS silencing caused extended leaf longevity and increased thickness of the leaves, with reducing sugar and starch contents indicating the compensation of energy loss.…”

“…DHS silencing caused extended leaf longevity and increased thickness of the leaves, with reducing sugar and starch contents indicating the compensation of energy loss. The silencing of DHS was accompanied by increased levels of proteins involved in ribosome complex composition, porphyrin and chlorophyll metabolism, and stilbenoid, diarylheptanoid, and gingerol biosynthesis [ 32 ]. In canola ( Brassica napus cv.…”

Virus induced PhFTRv gene silencing results in yellow-green leaves and reduced cold tolerance in petunia

“…Chlorophyll content was determined according to our previously described protocol (Liu et al 2019). Approximately 1.5 g of leaves were harvested and freeze-dried, and three replicate methanol extractions were prepared.…”