The superwoman1‐cleistogamy2 mutant is a novel resource for gene containment in rice

Abstract

SummaryOutcrossing between cultivated plants and their related wild species may result in the loss of favourable agricultural traits in the progeny or escape of transgenes in the environment. Outcrossing can be physically prevented by using cleistogamous (i.e. closed‐flower) plants. In rice, flower opening is dependent on the mechanical action of fleshy organs called lodicules, which are generally regarded as the grass petal equivalents. Lodicule identity and development are specified by the action of protein complexes involving the SPW1 and OsMADS2 transcription factors. In the superwoman1‐cleistogamy1 (spw1‐cls1) mutant, SPW1 is impaired for heterodimerization with OsMADS2 and consequently spw1‐cls1 shows thin, ineffective lodicules. However, low temperatures help stabilise the mutated SPW1/OsMADS2 heterodimer and lodicule development is restored when spw1‐cls1 is grown in a cold environment, resulting in the loss of the cleistogamous phenotype. To identify a novel, temperature‐stable cleistogamous allele of SPW1, targeted and random mutations were introduced into the SPW1 sequence and their effects over SPW1/OsMADS2 dimer formation were assessed in yeast two‐hybrid experiments. In parallel, a novel cleistogamous allele of SPW1 called spw1‐cls2 was isolated from a forward genetic screen. In spw1‐cls2, a mutation leading to a change of an amino acid involved in DNA binding by the transcription factor was identified. Fertility of spw1‐cls2 is somewhat decreased under low temperatures but unlike for spw1‐cls1, the cleistogamous phenotype is maintained, making the line a safer and valuable genetic resource for gene containment.

iTRAQ-based quantitative proteome analysis reveals metabolic changes between a cleistogamous wheat mutant and its wild-type wheat counterpart

“…The molecular mechanism for cleistogamy has been intensively studied in rice (Maeng et al, 2006; Yoshida et al, 2007; Ohmori et al, 2012; Ni et al, 2014; Lombardo et al, 2017) and barley (Turuspekov et al, 2004; Hori et al, 2005; Nair et al, 2010; Wang et al, 2013, 2015; Zhang et al, 2016). However, the molecular mechanism for cleistogamy in wheat remains unclear, though it is known that the lodicule is a key factor in glume opening/closing in the monocotyledon.…”

“…A third rice mutant, spw1-cls , has normal stamens, but the lodicules are transformed homeotically into lodicule-glume mosaic organs, thereby engendering cleistogamy with temperature-sensitivity (Yoshida et al, 2007; Ohmori et al, 2012). A novel temperature-stable cleistogamous mutant, spw1-cls2 , can maintain the cleistogamous phenotype under low temperatures (Lombardo et al, 2017). The glumes open in the flowering stage because the swelling of the lodicule is primarily responsible for pushing the lemma and palea, thereby opening the floret (Nair et al, 2010).…”

The cleistogamy of the <i>superwoman1-cleistogamy1</i> mutation is sensitive to low temperatures during the lodicule-forming stage

“…A novel rice cleistogamous spw1-cls2 mutant was reported ( Lombardo et al 2017 ). spw1-cls2 has a missense mutation at a different position in SPW1 compared with spw1-cls1 , and its mechanism of cleistogamy differs from that of spw1-cls1 .…”

Peer Review #2 of "iTRAQ-based quantitative proteome analysis reveals metabolic changes between a cleistogamous wheat mutant and its wild-type wheat counterpart (v0.2)"

“…Manuscript to be reviewed Lodicules play an important role in glume opening/closing in wheat The molecular mechanism for cleistogamy has been intensively studied in rice (Maeng et al, 2006;Yoshida et al, 2007;Ohmori et al, 2012;Ni et al, 2014;Lombardo et al, 2017) and barley (Turuspekov et al, 2004;Hori et al, 2005;Nair et al, 2010;Wang et al, 2013Wang et al, , 2015Zhang et al, 2016). However, the molecular mechanism for cleistogamy in wheat remains unclear, though it is known that the lodicule is a key factor in glume opening/closing in the monocotyledon.…”

“…A third rice mutant, spw1-cls, has normal stamens, but the lodicules are transformed homeotically into lodicule-glume mosaic organs, thereby engendering cleistogamy with temperature-sensitivity (Yoshida et al, 2007;Ohmori et al, 2012). A novel temperature-stable cleistogamous mutant, spw1-cls2, can maintain the cleistogamous phenotype under low temperatures (Lombardo et al, 2017). The glumes open in the flowering stage because the swelling of the lodicule is primarily responsible for pushing the lemma and palea, thereby opening the floret (Nair et al, 2010).…”