Gene Expression Profiles Deciphering Leaf Senescence Variation between Early- and Late-Senescence Cotton Lines

Abstract

Leaf senescence varies greatly among genotypes of cotton (Gossypium hirsutium L), possibly due to the different expression of senescence-related genes. To determine genes involved in leaf senescence, we performed genome-wide transcriptional profiling of the main-stem leaves of an early- (K1) and a late-senescence (K2) cotton line at 110 day after planting (DAP) using the Solexa technology. The profiling analysis indicated that 1132 genes were up-regulated and 455 genes down-regulated in K1 compared with K2 at 110 DAP. The Solexa data were highly consistent with, and thus were validated by those from real-time quantitative PCR (RT-PCR). Most of the genes related to photosynthesis, anabolism of carbohydrates and other biomolecules were down-regulated, but those for catabolism of proteins, nucleic acids, lipids and nutrient recycling were mostly up-regulated in K1 compared with K2. Fifty-one differently expressed hormone-related genes were identified, of which 5 ethylene, 3 brassinosteroid (BR), 5 JA, 18 auxin, 8 GA and 1 ABA related genes were up-regulated in K1 compared with K2, indicating that these hormone-related genes might play crucial roles in early senescence of K1 leaves. Many differently expressed transcription factor (TF) genes were identified and 11 NAC and 8 WRKY TF genes were up-regulated in K1 compared with K2, suggesting that TF genes, especially NAC and WRKY genes were involved in early senescence of K1 leaves. Genotypic variation in leaf senescence was attributed to differently expressed genes, particularly hormone-related and TF genes.

Physiological and molecular adjustment of cotton to waterlogging at peak-flowering in relation to growth and yield

“…The LHCB expression level in early-senescence cotton line was lower than in late-senescence cotton line. The chlorophyll content and photosynthesis in earlysenescence cotton line were also lower than in late-senescence cotton line at 95 and 110 days after planting, suggesting that the decreased chlorophyll content and photosynthesis in earlysenescence cotton might be attribute to reduced expression of LHCB (Kong et al, 2013). In the present study, expression of the GhLHCB in cotton leaves and the P n rate were decreased under waterlogging stress, suggested that the reduced GhLHCB expression might be an attribute to the reduction in P n rate.…”

Integrating transcriptomic and metabolomic analysis to understand natural leaf senescence in sunflower

“…At the transcriptional level, the regulation of senescence has been well studied in model species such as A. thaliana (Gepstein et al, 2003;Lim et al, 2003;Lin and Wu, 2004). Furthermore, this process has been partially assessed in other species such as rice (Lee et al, 2001), tobacco (Pageau et al, 2006), pea (Pic et al, 2002), wheat (Uauy et al, 2006), cotton (Kong et al, 2013), maize (Sekhon et al, 2012;Zhang et al, 2014), turnip (Gombert et al, 2006), barley (Hollmann et al, 2014;Jukanti et al, 2008) and sunflower (Cabello et al, 2006;Fernandez et al, 2012a;Moschen et al, 2014). Transcription factors (TFs) are key proteins in the regulation of gene expression and signal transduction networks regulating different biological processes.…”

GhNAC18, a novel cotton (Gossypium hirsutum L.) NAC gene, is involved in leaf senescence and diverse stress responses

“…This implies that GhNAC18 may have a significant role in the young leaves. Although, NACs have been reported to be involved in early and late senescence in upland cotton (Kong et al, 2013), GhNAC18 seemed to have a different trend during aging process because, its transcript abudance decreases as aging advances. Premature leaf senescence causes poor or low yield in cotton in early maturing cultivars (Wright, 1998).…”