Dual functions of the ZmCCT-associated quantitative trait locus in flowering and stress responses under long-day conditions

Abstract

BackgroundPhotoperiodism refers to the ability of plants to measure day length to determine the season. This ability enables plants to coordinate internal biological activities with external changes to ensure normal growth. However, the influence of the photoperiod on maize flowering and stress responses under long-day (LD) conditions has not been analyzed by comparative transcriptome sequencing. The ZmCCT gene was previously identified as a homolog of the rice photoperiod response regulator Ghd7, and associated with the major quantitative trait locus (QTL) responsible for Gibberella stalk rot resistance in maize. However, its regulatory mechanism has not been characterized.ResultsWe mapped the ZmCCT-associated QTL (ZmCCT-AQ), which is approximately 130 kb long and regulates photoperiod responses and resistance to Gibberella stalk rot and drought in maize. To investigate the effects of ZmCCT-AQ under LD conditions, the transcriptomes of the photoperiod-insensitive inbred line Huangzao4 (HZ4) and its near-isogenic line (HZ4-NIL) containing ZmCCT-AQ were sequenced. A set of genes identified by RNA-seq exhibited higher basal expression levels in HZ4-NIL than in HZ4. These genes were associated with responses to circadian rhythm changes and biotic and abiotic stresses. The differentially expressed genes in the introgressed regions of HZ4-NIL conferred higher drought and heat tolerance, and stronger disease resistance relative to HZ4. Co-expression analysis and the diurnal expression rhythms of genes related to stress responses suggested that ZmCCT and one of the circadian clock core genes, ZmCCA1, are important nodes linking the photoperiod to stress tolerance responses under LD conditions.ConclusionOur study revealed that the photoperiod influences flowering and stress responses under LD conditions. Additionally, ZmCCT and ZmCCA1 are important functional links between the circadian clock and stress tolerance. The establishment of this particular molecular link has uncovered a new relationship between plant photoperiodism and stress responses.Electronic supplementary materialThe online version of this article (doi:10.1186/s12870-016-0930-1) contains supplementary material, which is available to authorized users.

Single-gene resolution of locally adaptive genetic variation in Mexican maize

“…SNPs in Zm00001d046909 are associated with daily temperature variability during the growing season, and show G × E effects for ear mass and temperature, precipitation, and elevation. The candidates Zm00001d024909 (CCT domain transcription factor) and Zm00001d010752 ( pebp8, zcn8 ) are known to be involved in photoperiod sensitivity, flowering time, and long-day stress response (62; 63; 64). The former shows environmental association with mean temperature and is a candidate in our G × E analysis between ear mass and temperature, precipitation, and elevation, and the latter is a G × E candidate for flowering time and temperature as well as annual precipitation and wet days).…”

MicroRNA 399 as a potential integrator of photo-response, phosphate homeostasis, and sucrose signaling under long day condition

“…The CCT domain gene ( GRMZM2G381691 ) in qDPS10 was considered as a candidate gene for photoperiod sensitivity. Additionally, higher transcript levels were observed in the ZmCCT -associated near-isogenic line (NIL), than that in its recurrent parent, H4 under LD conditions [ 12 ].…”

Global transcriptome analysis of the maize (Zea mays L.) inbred line 08LF during leaf senescence initiated by pollination-prevention

“…GO term fusion and restriction with P < 0.05 were employed, which integrate GO categories and create a functionally organized GO category network based on overlap between different GO categories and significance. The intervals of each GO level were set at a min level = 5 and a max level = 11, and a 2 gene minimum per category as described by Ku et al[ 36 ] Analysis was conducted using a right-sided hypergeometric test for enrichment based on the ClueGO Zea Mays L. reference genome.…”