An open‐flower mutant ofMelilotus alba: Potential for floral‐dip transformation of a papilionoid legume with a short life cycle?

Abstract

This paper describes an open-flower mutant, designated opf, that we discovered in a genetic screen of fast neutron bombardment mutants in an attempt at floral-dip transformation of Melilotus alba (Fabaceae; white sweetclover), an alternative papilionoid legume host for Sinorhizobium meliloti. The opf mutant developed flowers with reflexed sepals and petals, thereby exposing the stamens and carpel, whereas wild-type sweetclover inflorescences developed closed flowers where the young stamens and carpel remain covered during the early stages of flower development. Based on crosses with the wild type, the mutant segregated as a single, Mendelian recessive. Crosses were successful only when the opf mutant served as the female parent, suggesting that the mutant was male sterile. However, no obvious differences from wild-type stamen development were observed in the opf mutant. The anther defect was due to indehiscence. However, as the plants approached the end of their life cycle, the frequency of selfing increased. We also investigated whether the opf mutant could be transformed via Agrobacterium tumefaciens floral-dip infiltration because open flowers like those of Arabidopsis appear to be more readily transformable. However, similar to wild-type M. alba, the opf mutant is refractory to floral-dip transformation by Agrobacterium tumefaciens.

The impact of aqueous and N-hexane extracts of three Fabaceae species on seed germination and seedling growth of some broadleaved weed species

“…The plant rapidly grows up to 4.5 to 6.0 m in one year and its flowers develop into mature pods one year after germination [37]. Melilotus alba has 0.3-2.6 m height, upright stem, coarse or fine, ground or channeled usually pubescent or has piles near the tip [38]. Lettuce (Lactuca sativa) is considered highly sensitive to allelopathic action of phytotoxic compounds; therefore, widely used as target species in preliminary screening of allelopathic plants [39].…”

Amenability of an Agrobacterium tumefaciens-mediated shoot apical meristem-targeted in planta transformation strategy in Mango (Mangifera indica L.)

“…Tissue culture-independent in planta transformation has been demonstrated in many crops such as Brassica rapa , 17 B. napus , 18 B. campestris , 19 Arabidopsis thaliana , 20 Medicago truncatula , 21 Raphanus sativus , 22 Solanum lycopersicum , 23 Glycine max , 24 Melilotus alba , 25 Zea mays , 26 Oryza sativa , 27 Citrus maxima 28 and Passiflora edulis . 29 Several in planta transformation strategies have been developed using different tissues, i.e ., seed, epicotyl, shoot apical meristem, flower, fruit etc.…”

Germline transformation of Artemisia annuaL. plant via in planta transformation technology “Floral dip”

“…Bechtold et al., 1998 [34] were the first to demonstrate the floral-dip transition in Arabidopsis thaliana , which was later refined by Clough and Bent, 1998 [32] . Later, using a similar approach, Curtis and Nam (2001) [35] reported the successful generation of transgenic radish and thereafter many more scientists that have reported the transgenic plant production of tomato [36] , wheat [37] , rapeseed [38] , white sweet clover [39] , camelina [40] , flax [41] , and rice [42] . Here, we for the first time, demonstrated the efficacy of the floral dipping method for the Asteraceae family member i.e., Artemisia annua L. with enhanced expression of artemisinin biosynthesis genes, which may possibly increase the artemisinin biosynthesis and its yield.…”