Gibberellin Signaling Repressor LlDELLA1 Controls the Flower and Pod Development of Yellow Lupine (Lupinus luteus L.)

Abstract

Precise control of generative organ development is of great importance for the productivity of crop plants, including legumes. Gibberellins (GAs) play a key role in the regulation of flowering, and fruit setting and development. The major repressors of GA signaling are DELLA proteins. In this paper, the full-length cDNA of LlDELLA1 gene in yellow lupine (Lupinus luteus L.) was identified. Nuclear-located LlDELLA1 was clustered in a second phylogenetic group. Further analyses revealed the presence of all conserved motifs and domains required for the GA-dependent interaction with Gibberellin Insensitive Dwarf1 (GID1) receptor, and involved in the repression function of LlDELLA1. Studies on expression profiles have shown that fluctuating LlDELLA1 transcript level favors proper flower and pod development. Accumulation of LlDELLA1 mRNA slightly decreases from the flower bud stage to anther opening (dehiscence), while there is rapid increase during pollination, fertilization, as well as pod setting and early development. LlDELLA1 expression is downregulated during late pod development. The linkage of LlDELLA1 activity with cellular and tissue localization of gibberellic acid (GA3) offers a broader insight into the functioning of the GA pathway, dependent on the organ and developmental stage. Our analyses provide information that may be valuable in improving the agronomic properties of yellow lupine.

Anther Dehiscence Is Regulated By Gibberellic Acid In Yellow Lupine (Lupinus Luteus L.)

“…For years, there has been a hypothesis that the reason for excessive ower separation may be incorrect stamen development, and as a consequence insu cient pollination, fertilization, and pod setting, which nally reduces yield. Our earlier study has shown that changing level of LlDELLA1 mRNA, encoding major repressors of GA signaling, supports the correct ower and pod development [34]. Interestingly, the expression of LlDELLA1 in the closed-ower bud phase is relatively high and then slightly decreased until the anther opening, while during pollination, fertilization and early pod development the gradual increase of transcript level is observed.…”

“…Changes in the yellow lupine anther structure during dehiscence program Dehiscence of anther is a multistage process which was examined in such species as A. thaliana, O. sativa, Zea mays, Nicotiana tabacum and Solanum lycopersicum [4]. In our previous study we showed that yellow lupine anther opening takes place in the fourth stage of ower development [34]. Therefore, it seems interesting to study the process of late anther development and the accompanying alterations in tested species.…”

“…Taper. Obtained from the Plant Breeding Station Wiatrowo (Poland) the seeds were prepared and sown as described by [34] in the experimental eld in Pędzewo, Kuyavian-Pomeranian Voivodeship in north-central Poland (53°05′02″N 18°21′28″E). The plants were cultivated on the 5th soil class as recommended by the manufacturer.…”

“…In yellow lupine, studies on expression pro le have shown that uctuating transcript level of LlDELLA1, which encodes the main repressor of GA signaling, promotes proper ower and pod development. LlDELLA1 mRNA level is lowest when the anthers are opened and then increases during the fertilization and early pod developmental stages [34].…”

“…Yellow lupine is also characterized by the ability to x atmospheric nitrogen, as well as high protein content in seeds; therefore it is worldwide used as food and feed source. Nevertheless, this legume plant has problem of premature ower abortion [32,33,34,35]. For years, there has been a hypothesis that the reason for excessive ower separation may be incorrect stamen development, and as a consequence insu cient pollination, fertilization, and pod setting, which nally reduces yield.…”