Understanding Apple Varieties and Their Resistance to Apple Scab Disease

Greg Howard
7th September, 2024

Understanding Apple Varieties and Their Resistance to Apple Scab Disease

Image Source: Natural Science News, 2024

Key Findings

  • Researchers at the University of Angers, France, studied the genetic mechanisms behind partial resistance to apple scab
  • They identified specific genes that change their activity when apples are infected with the scab-causing fungus
  • These findings can help breeders develop new apple varieties with stronger and more durable resistance to apple scab
Apple scab, caused by the fungus Venturia inaequalis, is a significant disease affecting apple crops worldwide. Traditional methods of control, such as using fungicides and breeding for resistance, have had varying degrees of success. One promising approach is the use of quantitative trait loci (QTL) to enhance partial resistance to apple scab. A recent study conducted by researchers at the University of Angers, France, investigated the molecular mechanisms underlying three specific QTLs (qT1, qF11, and qF17) that contribute to this partial resistance[1]. The study aimed to understand how these QTLs function at the genetic level to confer resistance. To achieve this, the researchers performed RNA sequencing on sixteen apple genotypes with different combinations of resistant and susceptible alleles of the three QTLs. The sequencing was done both before and five days after inoculation with Venturia inaequalis. This approach allowed the researchers to identify differentially expressed genes that are potentially involved in the resistance mechanism. The findings from this study are significant because they provide a detailed transcriptomic profile of the apple genotypes under study. This profile includes the analysis of genes that are differentially expressed when the plants are infected with the fungus compared to when they are not. By identifying these genes, researchers can pinpoint candidate genes and pathways that are implicated in the resistance conferred by the QTLs. This study builds on previous research that has identified specific QTLs for apple scab resistance. For instance, earlier studies have shown that the QTLs qF11 and qF17 are associated with resistance to different isolates of Venturia inaequalis[2]. Another study demonstrated that plant resistance inducers, such as acibenzolar-S-methyl (ASM), can enhance resistance when combined with genetic resistance, potentially reducing disease symptoms by up to 100%[3]. The current study expands on these findings by providing a molecular basis for the observed resistance, thereby offering new avenues for breeding apples with enhanced resistance to scab. The practical implications of this research are substantial. By understanding the genetic basis of quantitative resistance, breeders can develop new apple varieties that combine both qualitative and quantitative resistance traits. This approach could diversify the selective pressures on the pathogen, making it more difficult for the fungus to overcome the resistance. This is particularly important given that some strains of Venturia inaequalis have already evolved to overcome major resistance genes like Vf[2]. Moreover, the study's data have been deposited in the Gene Expression Omnibus (GEO) repository, making them accessible to other researchers for further analysis. This openness can facilitate collaborative efforts to improve apple breeding strategies and develop more sustainable disease control methods. In conclusion, the research conducted by the University of Angers provides valuable insights into the genetic mechanisms underlying partial resistance to apple scab. By identifying differentially expressed genes associated with specific QTLs, this study lays the groundwork for future breeding programs aimed at developing apple varieties with robust and durable resistance to this devastating disease.

GeneticsBiochemPlant Science

References

Main Study

1) Phenotyping data coupled with RNA sequencing of apple genotypes exhibiting contrasted quantitative trait loci architecture for apple scab (Venturia inaequalis) resistance.

Published 6th September, 2024

https://doi.org/10.1016/j.dib.2024.110778

Related Studies

2) Genetic dissection of partial resistance to race 6 of Venturia inaequalis in apple.

Journal: Genome, Issue: Vol 46, Issue 2, Apr 2003

3) Acibenzolar-S-Methyl and Resistance Quantitative Trait Loci Complement Each Other to Control Apple Scab and Fire Blight.

https://doi.org/10.1094/PDIS-07-20-1439-RE


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