Maize adaptation across temperate climates was obtained via expression of two florigen genes

Abstract

Expansion of the maize growing area was central for food security in temperate regions. In addition to the suppression of the short-day requirement for floral induction, it required breeding for a large range of flowering time that compensates the effect of South-North gradients of temperatures. Here we show the role of a novel florigen gene, ZCN12, in the latter adaptation in cooperation with ZCN8. Strong eQTLs of ZCN8 and ZCN12, measured in 327 maize lines, accounted for most of the genetic variance of flowering time in platform and field experiments. ZCN12 had a strong effect on flowering time of transgenic Arabidopsis thaliana plants; a path analysis showed that it directly affected maize flowering time together with ZCN8. The allelic composition at ZCN QTLs showed clear signs of selection by breeders. This suggests that florigens played a central role in ensuring a large range of flowering time, necessary for adaptation to temperate areas.

Genome-wide association study reveals the genetic architecture of root hair length in maize

“…Nowadays, modern maize displays a large geographic distribution from tropical to temperate climate. Therefore, population structure is associated with significant differences in maize morphology [51]. In this study, we observed that root hair exhibits wide length variation with normal distribution.…”

Quantitative and population genomics suggest a broad role of staygreen loci in the drought adaptation of sorghum

“…Flowering time is a critical component of geographic adaptation (Lasky et al, 2015;Castelletti et al, 2020) and a potential contributor to drought adaptation via early-flowering drought escape (Blum, 2010). Among the six canonical sorghum photoperiodic flowering genes (Maturity1-Maturity6) characterized in U.S. germplasm, (Murphy et al, 2011(Murphy et al, , 2014Yang et al, 2014;Casto et al, 2019) we identified colocalization of associations only at Ma2 (Fig.…”

“…SbCN12 (also known as SbFT8) is a co-ortholog of the canonical florigen Arabidopsis FT gene and ortholog of maize ZCN12 (Yang et al, 2014;Castelletti et al, 2020), which was identified as a likely sorghum florigen based on conserved sequence and expression dynamics (Yang et al, 2014;Wolabu et al, 2016). The current GWAS findings, along with previous finding that SbCN12 explained up to 12% of variation in global nested association mapping population (Bouchet et al, 2017;Hu et al, 2019), provide strong support for the hypothesis that functional allelic variation exists at SbCN12.…”

“…and SbZfl1 could shed light on their role in flowering time evolution (Bomblies & Doebley, 2006;Castelletti et al, 2020) and facilitate development of molecular marker to recover locallyadaptive flowering time.…”

Coordinative regulation of plants growth and development by light and circadian clock

“…ZCN7 and ZCN8 (ZEA CENTRORADIALIS 8) have been identified as the strongest candidate genes for maize florigen (Meng et al 2011;Mascheretti et al 2015). ZCN8 together with, ZCN12 can directly affect the flowering time of maize, which is necessary for adaptation to temperate climates (Castelletti et al 2020). There are two GI homologs in maize which has been reported to be involved in photoperiodic flowering (Miller et al 2008).…”