MADS-Box Genes and Gibberellins Regulate Bolting in Lettuce (Lactuca sativa L.)

Abstract

Bolting in lettuce is promoted by high temperature and bolting resistance is of great economic importance for lettuce production. But how bolting is regulated at the molecular level remains elusive. Here, a bolting resistant line S24 and a bolting sensitive line S39 were selected for morphological, physiological, transcriptomic and proteomic comparisons. A total of 12204 genes were differentially expressed in S39 vs. S24. Line S39 was featured with larger leaves, higher levels of chlorophyll, soluble sugar, anthocyanin and auxin, consistent with its up-regulation of genes implicated in photosynthesis, oxidation-reduction and auxin actions. Proteomic analysis identified 30 differentially accumulated proteins in lines S39 and S24 upon heat treatment, and 19 out of the 30 genes showed differential expression in the RNA-Seq data. Exogenous gibberellins (GA) treatment promoted bolting in both S39 and S24, while 12 flowering promoting MADS-box genes were specifically induced in line S39, suggesting that although GA regulates bolting in lettuce, it may be the MADS-box genes, not GA, that plays a major role in differing the bolting resistance between these two lettuce lines.

Genome‐wide analysis of MADS‐box family genes during flower development in lettuce

“…In 2016, the global production of lettuce and chicory reached 691,102 tons (http://www.fao.org/faostat/en/#data/QC/visualize). Because of global warming, lettuce production is often adversely affected by heat stress (Chen et al, ; Han et al, ). Lettuce is a heat‐induced bolting species that when exposed to heat stress conditions becomes bitter and begins to bolt and flower as well as transition from vegetative to reproductive growth.…”

Quantitative Proteomics Analysis of Lettuce (Lactuca sativa L.) Reveals Molecular Basis-Associated Auxin and Photosynthesis with Bolting Induced by High Temperature

“…by directly binding to their regulatory sequences [ 16 ]. Han and colleagues from our laboratory [ 17 ] reported that, although GA regulates bolting in lettuce, it may be the MADS-box genes instead, which play a major role in differing the bolting resistance between a bolting resistant line and a bolting sensitive line. A total of 12 MADS-box transcription factors were dramatically induced in lettuce during bolting such as putative LsSOC1 , LsAP1 , LsFUL and LsAGL24 .…”

“…Recently, proteomics has been widely used in the exploration of the resistance mechanism or development characters of plants, such as heat resistance [ 18 ], cold resistance and salt resistance [ 19 ]. Applying the proteomics approach, the bolting pattern in several plant species has been analyzed, such as Brassica rapa [ 5 ], Lactuca sativa [ 17 ], and Arabidopsis thaliana [ 8 , 14 ]. Furthermore, the proteomics analysis of the molecular basis of bolting in lettuce (a non-vernalization plant) induced by a high temperature was reported by Han and colleagues from our laboratory [ 17 ].…”

“…Applying the proteomics approach, the bolting pattern in several plant species has been analyzed, such as Brassica rapa [ 5 ], Lactuca sativa [ 17 ], and Arabidopsis thaliana [ 8 , 14 ]. Furthermore, the proteomics analysis of the molecular basis of bolting in lettuce (a non-vernalization plant) induced by a high temperature was reported by Han and colleagues from our laboratory [ 17 ]. Due to the technological limitation of two-dimensional electrophoresis-based proteomics, only 30 proteins with differential abundance were identified in lettuce in the previous work from our laboratory [ 17 ].…”

Effects of Morphological Characterization in Different Bolting Period of Lettuce

“…Although lettuce cultivation has expanded quickly, most varieties of lettuce sold in China are foreign varieties. Furthermore, because lettuce prefers cold climates, the high temperatures in summer usually cause early bolting, which can seriously affect the eating texture and market price of the vegetable [1]. Therefore, detecting specific phenotypic changes between and after bolting can provide a theoretical basis for further study of lettuce bolting.…”