Quantitative proteomic analyses reveal that energy metabolism and protein biosynthesis reinitiation are responsible for the initiation of bolting induced by high temperature in lettuce (Lactuca sativa L.)

Abstract

Background Lettuce (Lactuca sativa L.), one of the most economically important leaf vegetables, exhibits early bolting under high-temperature conditions. Early bolting leads to loss of commodity value and edibility, leading to considerable loss and waste of resources. However, the initiation and molecular mechanism underlying early bolting induced by high temperature remain largely elusive. Results In order to better understand this phenomenon, we defined the lettuce bolting starting period, and the high temperature (33 °C) and controlled temperature (20 °C) induced bolting starting phase of proteomics is analyzed, based on the iTRAQ-based proteomics, phenotypic measurement, and biological validation by RT-qPCR. Morphological and microscopic observation showed that the initiation of bolting occurred 8 days after high-temperature treatment. Fructose accumulated rapidly after high-temperature treatment. During initiation of bolting, of the 3305 identified proteins, a total of 93 proteins exhibited differential abundances, 38 of which were upregulated and 55 downregulated. Approximately 38% of the proteins were involved in metabolic pathways and were clustered mainly in energy metabolism and protein synthesis. Furthermore, some proteins involved in sugar synthesis were differentially expressed and were also associated with energy production. Conclusions This report is the first to report on the metabolic changes involved in the initiation of bolting in lettuce. Our study suggested that energy metabolism and ribosomal proteins are pivotal components during initiation of bolting. This study could provide a potential regulatory mechanism for the initiation of early bolting by high temperature, which could have applications in the manipulation of lettuce for breeding.

Genome-Wide Identification and Expression Analysis of MAPK Gene Family in Lettuce (Lactuca sativa L.) and Functional Analysis of LsMAPK4 in High- Temperature-Induced Bolting

“…In the previous comparative proteomics, we found that among LsMAPKs proteins, LsMAPK3/4/9 were differentially expressed in high-temperature bolting of leaf lettuce [ 47 ]. The subsequent qRT–PCR indicated that the transcription level of LsMAPK4 among the above three LsMAPKs was markedly and continuously upregulated during high-temperature bolting.…”

“…Moreover, the specific regulatory mechanism of high-temperature bolting in lettuce remains unclear, and MAPK has not been reported to play a role in the high temperature-induced bolting of lettuce. Early in this research, we screened differentially expressed MAPK cascade members involved in lettuce bolting at high temperatures, including LsMAPK3, LsMAPK4, LsMAPK9, and LsMAPKK5 protein, using comparative proteomics [ 47 ]. Recognizing the crucial role of MAPK in plant growth, development, and stress response, we conducted a genome-wide screening, identification, and bioinformatics analysis of the MAPK gene family in lettuce, determined the differential expression of the MAPK gene family at high temperature, and conducted a virus-induced gene silencing (VIGS) evaluation on LsMAPK4 with significant differential expression.…”

Genome-wide screening and characterization of long noncoding RNAs involved in flowering/bolting of Lactuca sativa

“…LsSOC1 also acts by activating bolting upon high temperatures. In addition, MADS-box genes and GAs can as well regulate bolting in lettuce [ 10 ].…”

Agronomic characteristics and quality of lettuce cultivars in different crop seasons in western Alagoas, Brazil

“…However, lettuce production in the Semiarid region of the Northeast of Brazil is lower when compared to regions with milder climates (YURI et al, 2017). It occurs because lettuce is directly affected by variations in temperature and light, which can change its development cycle (HAO et al, 2021).…”