The polyamine spermine induces cystocarp development in the seaweed Grateloupia (Rhodophyta)

Abstract

Polyamines such as putrescine, spermidine and spermine are ubiquitous aliphatic amines involved in reproductive events in plants and algae, and first become evident through changes in endogenous levels during reproductive development. To examine whether the differences observed in polyamines, during carposporogenesis, in the red alga Grateloupia, followed a specific pattern as is seen in other organisms, infertile axes (i.e. not showing cystocarps) were excised from the same holdfast of female fertilized individuals (i.e. showing cystocarps in other axes), and cultivated until the cystocarps became visible. Changes in the endogenous levels of free putrescine, spermidine and spermine were monitored over the 8 days of culture. The activity of enzymes related to polyamine metabolism, such as L-ornithine decarboxylase (ODC), diamine oxidase and polyamine oxidase, was measured at the beginning and end of the experimental period. Up to 50% of the infertile axes became fertile and produced cystocarps at a density of 1.91 ± 0.1 cystocarps mm À2 after 8 days. The endogenous content of spermine increased markedly over the first 5 days of culture, then decreased to the initial level by day 8.Spermidine followed a similar pattern to spermine, whereas putrescine remained at high levels, until day 5 when it decreased abruptly. The activity of ODC was less on day 8 than on day 0, whereas the activities of diamine oxidase and polyamine oxidase increased. In parallel experiments with explants from infertile axes, exogenously added spermine (10 À6 M) increased the number of cystocarps, and reversed the effect of cyclohexylamine (CHA), which is known to inhibit polyamine synthesis in Grateloupia. Serial sectioning and microscopic observation of specimens from explants cultivated in 10 À6 M spermine indicated that cystocarp development was induced. The results suggest that, during transition from infertile to fertile spermine is accumulated, thus favouring the development of cystocarps, given the presumed role of spermine as an inducing agent.

Differential responses to cadmium induced oxidative stress in marine macroalga Ulva lactuca (Ulvales, Chlorophyta)

“…Further, polyamine (PAs)-aliphatic amines with relatively low molecular mass have also been studied in macroalgae with respect to their involvement in cell division (Cohen et al 1984;Garcia Jimenez et al 1998) and protection from hypo saline stress (Lee 1998;Garcia Jimenez et al 2007). Sacramento et al (2004Sacramento et al ( , 2007 and Guzman-Uriostegui et al (2002) have reported their role in maturation of reproductive structure in Grateloupia and Gracilaria cornea respectively, but their function as metal chelator to protect the seaweeds from metal induced oxidative stress has not been reported.…”

Polyamines increase carpospore output and growth during in vitro cultivation of Hydropuntia cornea

“…Guzmán-Urióstegui et al (2002) reported a sharp increase in endogenous levels of PAs during cystocarp development at early post-fertilization events as opposed to the PAs found in female thalli without fertilized carpogonia and mature cystocarp. Sacramento et al (2007) also reported that infertile axes from Grateloupia gametophyte thalli accumulated more PAs than those axes with cystocarps.…”

“…In marine algae, PAs have been studied with respect to their occurrence in various algal groups and their involvement in cell division (Marian et al 2000) and there is evidence for the involvement of endogenous PAs in different stages of cystocarp maturation during reproduction in Gracilaria cornea and Grateloupia sp. (Guzmán-Urióstegui et al 2002;Sacramento et al 2007).…”

Algal Morpho‐Inducers

“…In this regard, ethylene (Figure 9.2b), a gaseous hormone involved in flowering and fruit abscission in higher plants, was recently shown to play an important role in tetrasporogenesis in red macroalgae (Order Gelidiales, Pterocladiella capillacea; García-Jim enez and Robaina, 2012). Likewise, in red macroalgae, polyamines (spermine, spermidine and putrescine; Figure 9.2c) have been shown to induce the formation of cystocarps (Order Halymeniales, Grateloupia, Sacramento, Garcia-Jimenez, and Robaina, 2007;Sacramento et al, 2007) and carpospores and their subsequent development into sporelings (Order Gracilariales Hydropuntia cornea, GuzmanUriostegui et al, 2012).…”