Correction: Overexpression of the AtSHI Gene in Poinsettia, Euphorbia pulcherrima, Results in Compact Plants

Abstract

Euphorbia pulcherrima, poinsettia, is a non-food and non-feed vegetatively propagated ornamental plant. Appropriate plant height is one of the most important traits in poinsettia production and is commonly achieved by application of chemical growth retardants. To produce compact poinsettia plants with desirable height and reduce the utilization of growth retardants, the Arabidopsis SHORT INTERNODE (AtSHI) gene controlled by the cauliflower mosaic virus 35S promoter was introduced into poinsettia by Agrobacterium-mediated transformation. Three independent transgenic lines were produced and stable integration of transgene was verified by PCR and Southern blot analysis. Reduced plant height (21-52%) and internode lengths (31-49%) were obtained in the transgenic lines compared to control plants. This correlates positively with the AtSHI transcript levels, with the highest levels in the most dwarfed transgenic line (TL1). The indole-3-acetic acid (IAA) content appeared lower (11-31% reduction) in the transgenic lines compared to the wild type (WT) controls, with the lowest level (31% reduction) in TL1. Total internode numbers, bract numbers and bract area were significantly reduced in all transgenic lines in comparison with the WT controls. Only TL1 showed significantly lower plant diameter, total leaf area and total dry weight, whereas none of the AtSHI expressing lines showed altered timing of flower initiation, cyathia abscission or bract necrosis. This study demonstrated that introduction of the AtSHI gene into poinsettia by genetic engineering can be an effective approach in controlling plant height without negatively affecting flowering time. This can help to reduce or avoid the use of toxic growth retardants of environmental and human health concern. This is the first report that AtSHI gene was overexpressed in poinsettia and transgenic poinsettia plants with compact growth were produced.

Genome-Wide Analysis of the Shi-Related Sequence Family and Functional Identification of GmSRS18 Involving in Drought and Salt Stresses in Soybean

“…The mutant of AtSHI showed resembled phenotype of a mutant defective in gibberellin (GA) biosynthesis, demonstrating that AtSHI may be involved in the GA signaling pathway [15]. Overexpression of AtSHI in the ornamental Kalanchoë and the poinsettia caused compact phenotype of transgenic plants [16,17]. Interestingly, the members of the SHI/STY family had the redundant function in the progress of auxin biosynthesis probably by regulating the photomorphogenesis-related genes (HY5, BBX21, and BBX22) [11,13,18,19].…”

Transgenic Kalanchoë blossfeldiana, Containing Individual rol Genes and Open Reading Frames Under 35S Promoter, Exhibit Compact Habit, Reduced Plant Growth, and Altered Ethylene Tolerance in Flowers

“…These approaches have been pursued in several ornamental plants, e.g., Calibrachoa (Gennarelli et al, 2009), Kalanchoë (Christensen et al, 2008), Mecardonia (Pérez de la Torre et al, 2018), Petunia (Mishiba et al, 2006), and poinsettia (Islam et al, 2013). Some of these strategies target alteration of gibberellic acid (GA) metabolism; GA 20 oxidases have silenced (Topp et al, 2008), GA 2 oxidases have been over-expressed (Gargul et al, 2013), the Arabidopsis thaliana Short Internodes gene has been overexpressed (Lütken et al, 2010;Islam et al, 2013), and knotted homeobox genes have been modulated (Lütken et al, 2011). Although being successful, these strategies unfortunately all fall under the EU GMO regulation (European Union, 2001) and are, due to legislation and low public acceptance, presently not applicable for the horticultural market in e.g., Europe.…”