Analyses between Reproductive Behavior, Genetic Diversity and Pythium Responsiveness in Zingiber spp. Reveal an Adaptive Significance for Hemiclonality

Abstract

Mode of reproduction is generally considered to have long-range evolutionary implications on population survival. Because sexual reproduction produces genetically diverse genotypes, this mode of reproduction is predicted to positively influence the success potential of offspring in evolutionary arms race with parasites (Red queen) whereas, without segregation and recombination, the obligate asexual multiplication may push a species into extinction due to the steady accumulation of deleterious mutations (Muller’s ratchet). However, the extent of linearity between reproductive strategies, genetic diversity and population fitness, and the contributions of different breeding strategies to population fitness are yet to be understood clearly. Genus Zingiber belonging to the pan-tropic family Zingiberaceae represents a good system to study contributions of different breeding behavior on genetic diversity and population fitness, as this genus comprises species with contrasting breeding systems. In this study, we analyzed breeding behavior, amplified fragment length polymorphism diversity and response to the soft-rot pathogen Pythium aphanidermatum in 18 natural populations of three wild Zingiber spp.: Z. neesanum, Z. nimmonii, and Z. zerumbet, together with the obligately asexual cultivated congener, ginger (Z. officinale). Ginger showed an exceptionally narrow genetic base, and adding to this, all the tested cultivars were uniformly susceptible to soft-rot. Concordant with the postulates of Muller’s ratchet, the background selection may be continuously pushing ginger into the ancestral state, rendering it inefficient in host-pathogen coevolution. Z. neesanum and Z. nimmonii populations were sexual and genetically diverse; however, contrary to Red Queen expectations, the populations were highly susceptible to soft-rot. Z. zerumbet showed a hemiclonal breeding behavior. The populations inhabiting forest understory were large and continuous, sexual and genetically diverse, but were susceptible, whereas populations inhabiting the revenue land were fragmented and monoclonal, but were resistant. It may be possible that, when genetic recombination becomes at a premium due to the genetic constraints imparted by habitat fragmentation or pathogen pressure, Z. zerumbet

The complete chloroplast genome sequence of Alpinia oxyphylla Miq. and comparison analysis within the Zingiberaceae family

“…The GC content of the A . oxyphylla chloroplast genome is 36.17%, which is similar to other chloroplast genomes previously reported [14,15,30]. The genome consists of 132 genes, including 87 distinct protein-coding genes, four distinct rRNA genes and 37 distinct tRNA genes, 21 of which were duplicated in the IR regions, 12 in the SSC region and 84 in the LSC region (Table 1).…”

Analysis of Microbial Diversity in Soil under Ginger Cultivation

“…The extent of the diversity of microorganisms in soil is critical to the maintenance of health and quality of soil and plant, as a wide range of microorganisms is involved in important soil functions [ 20 ]. Recently, there have been a few studies on reports of ginger diseases [ 14 , 15 , 21 , 22 ]. However, to the best of our knowledge, the reports on soil microbes in ginger fields are limited.…”

Propagação in vitro de Zingiber spectabile

“…The germination of Z. meesanum, Z. nimmonii and Z. zirumbet seed was low, the average was below of 35% under continuous temperature of 18.16%, 23.16% and 34.33%, respectively (THOMAS et al, 2016).…”

“…(Z. meesanum, Z. nimmonii and Z. zerumbet) was evaluated in different geographic region in the south of India. Where Z. neesanum and Z. nimmonii produced seeds in all the populations evaluated, but Z. zerumbetc produced seed only in three areas of ten evaluated (THOMAS et al, 2016).…”

“…Over the senescence process of inflorescence, the bracts open and the seeds are exposed. Some species of the family Zingiberaceae rarely produced fruit, this can be incompatibility problems or absence of pollinator (CHOON et al, 2016;THOMAS et al, 2016). The presence of seed is not reported for most areas of Z. spectabile cultivation.…”