Plant Cell Reports

, Volume 30, Issue 12, pp 2267–2279

Expression of KxhKN4 and KxhKN5 genes in Kalanchoë blossfeldiana ‘Molly’ results in novel compact plant phenotypes: towards a cisgenesis alternative to growth retardants

  • Henrik Lütken
  • Marina Laura
  • Cristina Borghi
  • Marian Ørgaard
  • Andrea Allavena
  • Søren K. Rasmussen
Original Paper

DOI: 10.1007/s00299-011-1132-9

Cite this article as:
Lütken, H., Laura, M., Borghi, C. et al. Plant Cell Rep (2011) 30: 2267. doi:10.1007/s00299-011-1132-9

Abstract

Many potted plants like Kalanchoë have an elongated natural growth habit, which has to be controlled through the application of growth regulators. These chemicals will be banned in the near future in all the EU countries. Besides their structural functions, the importance of homeotic genes to modify plant architecture appears evident. In this work, the full length cDNA of five KNOX (KN) genes were sequenced from K. x houghtonii, a viviparous hybrid. Two constructs with the coding sequence of the class I and class II homeobox KN genes, KxhKN5 and KxhKN4, respectively, were overexpressed in the commercially important ornamental Kalanchoë blossfeldiana ‘Molly’. Furthermore, a post-transcriptional gene silencing construct was made with a partial sequence of KxhKN5 and also transformed into ‘Molly’. Several transgenic plants exhibited compact phenotypes and some lines had a relative higher number of inflorescences. A positive correlation between gene expression levels and the degree of compactness was found. However, a correlation between the induced phenotypes and the number of inserted copies of the transgene were not observed, although line ‘70-10’ with a high copy number also had the highest expression level. Moreover, overexpression of KxhKN4 resulted in plants with dark green leaves due to an elevated content of chlorophyll, a highly desired property in the ornamental plant industry. These transgenic plants show that a cisgenesis approach towards production of compact plants with improved quality as an alternative to chemical growth retardants may be feasible.

Keywords

CisgenesisHomeotic geneKaryotypeKNOXPlant architectureVivipary

Supplementary material

299_2011_1132_MOESM1_ESM.doc (70 kb)
Online Resource 1. Species of origin, accession number and brief description of selected class I KNOX homeodomain proteins used for the phylogenetic analysis reported in Fig. 1. To improve results, sequence of Physcomitrella patens (fern) and Ceratopteris richardii (moss) were added; the homeodomain protein of Acetabularia acetabulum (algae) was used as out group. (DOC 70 kb)
299_2011_1132_MOESM2_ESM.doc (56 kb)
Online Resource 2. Species of origin, accession number and brief description of selected class II KNOX homeodomain proteins used for the phylogenetic analysis reported in Fig. 2. To improve results, sequence of Physcomitrella patens (fern), Ceratopteris richardii (moss) and Selaginella kraussiana (clubmoss) were added; the homeodomain protein of Acetabularia acetabulum (algae) was used as out group. (DOC 56 kb)
299_2011_1132_MOESM3_ESM.jpg (62 kb)
Online Resource 3. Representative chromosome pictures for selected KN lines (jpg 61 kb)

Copyright information

© Springer-Verlag 2011

Authors and Affiliations

  • Henrik Lütken
    • 1
  • Marina Laura
    • 2
  • Cristina Borghi
    • 2
  • Marian Ørgaard
    • 1
  • Andrea Allavena
    • 2
  • Søren K. Rasmussen
    • 1
  1. 1.Department of Agriculture and Ecology, Faculty of Life SciencesUniversity of CopenhagenFrederiksberg CDenmark
  2. 2.CRA, Unit of Research for FloricultureSan RemoItaly