Petaloid Male-sterile Plants from Carrot Cell Cultures

Abstract

<jats:p>An experiment was conducted to determine the types, extent, and heritability of new phenotypic variants recovered from carrot cell cultures initiated from mature tap-root explants of the male-fertile carrot (<jats:italic>Daucus carota</jats:italic> L.) `Slendero'. Embryogenic callus was transferred to plant-growth-regulator-free medium 66 days after culture initiation, and regenerated plantlets were harvested and eventually planted in a field. The tap roots of mature regenerated plants were vernalized at 5C for 9 weeks and replanted. Of 31 flowering regenerants, 25 exhibited some form of petaloid male sterility; the remaining six regenerants were male fertile. All plants from the same original explant were either all sterile or all fertile. Three generations of sterile regenerant × petaloid cytoplasmic male sterility (CMS) maintainer (M) progeny tests showed that the new CMS behaved in a similar manner to that previously reported. Comparison of mitochondrial DNA restriction patterns of sterile and fertile regenerants with those of `Slendero', petaloid CMS, petaloid M, and brown anther CMS lines resulted in the following conclusions: 1) the sterile regenerants exhibited patterns identical to the known petaloid CMS and 2) the fertile regenerants were different from the original `Slendero' and the sterile regenerants and nearly identical to a known petaloid CMS M line. The high frequency of CMS among regenerants from `Slendero' carrot cell cultures may provide an efficient method to develop sterile M tandem lines and corresponding new hybrid varieties.</jats:p>

Mitochondrial atp9 genes from petaloid male-sterile and male-fertile carrots differ in their status of heteroplasmy, recombination involvement, post-transcriptional processing as well as accumulation of RNA and protein product

“…According to the scenario we describe above, the status of enhanced ATP9 accumulation in the S p -cytoplasm is achieved most likely through the enhanced level of the atp9 - 1 sequence and its expressional dominance over atp9 - 3 . An assumption that expression of CMS in carrots relies on the dynamic mutual proportion between mutated and normal sequence factors could easily explain both cases of fertility reversion (Chahal et al 1998 ) and induction of petaloidy through in vitro culture (Wright et al 1996 ). In favor of a causal relationship between ATP9 over-expression and CMS is the reduced ATP9 accumulation, which was observed in the semi-fertile S p -cytoplasmic plants.…”

Morphological and Cytological Characterization of Petaloid-type Cytoplasmic Male Sterility in Camellia oleifera

“…This petaloid type of male sterility is genetically stable, is less affected by the environment, and is easy to identify. Petaloid stability is found in many crop species, including Solanum melongena (Chen et al, 2013), Brassica juncea (Yu et al, 2010(Yu et al, , 2014, Daucus carota (Kozik et al, 2012;Tan et al, 2017;Wolyn and Chahal, 1998;Wright et al, 1996), and Tagetes erecta (He et al, 2010;Kumar et al, 2017). In higher plants, the primary causes of CMS include abnormal microspore and tapetal cell development (Jiang et al, 2015;Luo et al, 2018;Sun et al, 2016;Xie et al, 2018), abnormal adenosine triphosphatase activity (Ji et al, 2014), and excessively high concentrations of Ca 2+ (Tian et al, 1998).…”