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Genome-wide digital transcript analysis of putative fruitlet abscission related genes regulated by ethephon in litchi.

Li C, Wang Y, Ying P, Ma W, Li J - Front Plant Sci (2015)

Bottom Line: Of these, there were 1867 early-responsive genes whose expressions were up- or down-regulated from 0 to 1 d after treatment.The most affected genes included those related to ethylene biosynthesis and signaling, auxin transport and signaling, transcription factors (TFs), protein ubiquitination, ROS response, calcium signal transduction, and cell wall modification.These genes could be clustered into four groups and 13 subgroups according to their similar expression patterns. qRT-PCR displayed the expression pattern of 41 selected candidate genes, which proved the accuracy of our DTA data.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, China Litchi Research Center, South China Agricultural University Guangzhou, China ; Physiological Laboratory for South China Fruits, College of Horticulture, South China Agricultural University Guangzhou, China.

ABSTRACT
The high level of physiological fruitlet abscission in litchi (Litchi chinensis Sonn.) causes severe yield loss. Cell separation occurs at the fruit abscission zone (FAZ) and can be triggered by ethylene. However, a deep knowledge of the molecular events occurring in the FAZ is still unknown. Here, genome-wide digital transcript abundance (DTA) analysis of putative fruit abscission related genes regulated by ethephon in litchi were studied. More than 81 million high quality reads from seven ethephon treated and untreated control libraries were obtained by high-throughput sequencing. Through DTA profile analysis in combination with Gene Ontology and KEGG pathway enrichment analyses, a total of 2730 statistically significant candidate genes were involved in the ethephon-promoted litchi fruitlet abscission. Of these, there were 1867 early-responsive genes whose expressions were up- or down-regulated from 0 to 1 d after treatment. The most affected genes included those related to ethylene biosynthesis and signaling, auxin transport and signaling, transcription factors (TFs), protein ubiquitination, ROS response, calcium signal transduction, and cell wall modification. These genes could be clustered into four groups and 13 subgroups according to their similar expression patterns. qRT-PCR displayed the expression pattern of 41 selected candidate genes, which proved the accuracy of our DTA data. Ethephon treatment significantly increased fruit abscission and ethylene production of fruitlet. The possible molecular events to control the ethephon-promoted litchi fruitlet abscission were prompted out. The increased ethylene evolution in fruitlet would suppress the synthesis and polar transport of auxin and trigger abscission signaling. To the best of our knowledge, it is the first time to monitor the gene expression profile occurring in the FAZ-enriched pedicel during litchi fruit abscission induced by ethephon on the genome-wide level. This study will contribute to a better understanding for the molecular regulatory mechanism of fruit abscission in litchi.

No MeSH data available.


Effect of ethephon treatment on fruitlet abscission (A) and ethylene production (B) in litchi. Each value represented the means of three biological replicates from nine different trees, with the standard error (SE) indicated by vertical bars. Significant differences at 0.05 level are indicated with asterisk (*) according to t-test.
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Figure 1: Effect of ethephon treatment on fruitlet abscission (A) and ethylene production (B) in litchi. Each value represented the means of three biological replicates from nine different trees, with the standard error (SE) indicated by vertical bars. Significant differences at 0.05 level are indicated with asterisk (*) according to t-test.

Mentions: CFAR and ethylene production in fruitlet were compared between the control and ethephon (ETH) treatment (Figure 1). The CFARs showed similar trends (Figure 1A), which gradually increased in the first day and had no visible difference. Two days after treatment, the CFAR in ETH-treated fruitlet was significantly higher than that in the control. Consequently, 100% of the fruitlet abscised by 4 d after ETH treatment, compared with a ~50% loss in the control, indicating that ETH treatment significantly accelerated fruitlet drop. In addition, a clear impact on ethylene production was also observed in ETH-treated fruitlet. Within 3 days of observation, ethylene production in the control fruitlet remained more or less flat and kept below 8 μl kg−1 h−1. While ethylene production in the ETH-treated fruitlet increased rapidly and continuously, and achieved nearly a ten-fold higher level at day 3 than the control (Figure 1B). The increase in ethylene production suggested that ethephon application probably accelerates the fruit drop following the induction of ethylene production in fruitlet.


Genome-wide digital transcript analysis of putative fruitlet abscission related genes regulated by ethephon in litchi.

Li C, Wang Y, Ying P, Ma W, Li J - Front Plant Sci (2015)

Effect of ethephon treatment on fruitlet abscission (A) and ethylene production (B) in litchi. Each value represented the means of three biological replicates from nine different trees, with the standard error (SE) indicated by vertical bars. Significant differences at 0.05 level are indicated with asterisk (*) according to t-test.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4493771&req=5

Figure 1: Effect of ethephon treatment on fruitlet abscission (A) and ethylene production (B) in litchi. Each value represented the means of three biological replicates from nine different trees, with the standard error (SE) indicated by vertical bars. Significant differences at 0.05 level are indicated with asterisk (*) according to t-test.
Mentions: CFAR and ethylene production in fruitlet were compared between the control and ethephon (ETH) treatment (Figure 1). The CFARs showed similar trends (Figure 1A), which gradually increased in the first day and had no visible difference. Two days after treatment, the CFAR in ETH-treated fruitlet was significantly higher than that in the control. Consequently, 100% of the fruitlet abscised by 4 d after ETH treatment, compared with a ~50% loss in the control, indicating that ETH treatment significantly accelerated fruitlet drop. In addition, a clear impact on ethylene production was also observed in ETH-treated fruitlet. Within 3 days of observation, ethylene production in the control fruitlet remained more or less flat and kept below 8 μl kg−1 h−1. While ethylene production in the ETH-treated fruitlet increased rapidly and continuously, and achieved nearly a ten-fold higher level at day 3 than the control (Figure 1B). The increase in ethylene production suggested that ethephon application probably accelerates the fruit drop following the induction of ethylene production in fruitlet.

Bottom Line: Of these, there were 1867 early-responsive genes whose expressions were up- or down-regulated from 0 to 1 d after treatment.The most affected genes included those related to ethylene biosynthesis and signaling, auxin transport and signaling, transcription factors (TFs), protein ubiquitination, ROS response, calcium signal transduction, and cell wall modification.These genes could be clustered into four groups and 13 subgroups according to their similar expression patterns. qRT-PCR displayed the expression pattern of 41 selected candidate genes, which proved the accuracy of our DTA data.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, China Litchi Research Center, South China Agricultural University Guangzhou, China ; Physiological Laboratory for South China Fruits, College of Horticulture, South China Agricultural University Guangzhou, China.

ABSTRACT
The high level of physiological fruitlet abscission in litchi (Litchi chinensis Sonn.) causes severe yield loss. Cell separation occurs at the fruit abscission zone (FAZ) and can be triggered by ethylene. However, a deep knowledge of the molecular events occurring in the FAZ is still unknown. Here, genome-wide digital transcript abundance (DTA) analysis of putative fruit abscission related genes regulated by ethephon in litchi were studied. More than 81 million high quality reads from seven ethephon treated and untreated control libraries were obtained by high-throughput sequencing. Through DTA profile analysis in combination with Gene Ontology and KEGG pathway enrichment analyses, a total of 2730 statistically significant candidate genes were involved in the ethephon-promoted litchi fruitlet abscission. Of these, there were 1867 early-responsive genes whose expressions were up- or down-regulated from 0 to 1 d after treatment. The most affected genes included those related to ethylene biosynthesis and signaling, auxin transport and signaling, transcription factors (TFs), protein ubiquitination, ROS response, calcium signal transduction, and cell wall modification. These genes could be clustered into four groups and 13 subgroups according to their similar expression patterns. qRT-PCR displayed the expression pattern of 41 selected candidate genes, which proved the accuracy of our DTA data. Ethephon treatment significantly increased fruit abscission and ethylene production of fruitlet. The possible molecular events to control the ethephon-promoted litchi fruitlet abscission were prompted out. The increased ethylene evolution in fruitlet would suppress the synthesis and polar transport of auxin and trigger abscission signaling. To the best of our knowledge, it is the first time to monitor the gene expression profile occurring in the FAZ-enriched pedicel during litchi fruit abscission induced by ethephon on the genome-wide level. This study will contribute to a better understanding for the molecular regulatory mechanism of fruit abscission in litchi.

No MeSH data available.