Abstract
Asparagus kiusianus, an important wild relative of cultivated asparagus (A. officinalis), exhibits resistance to stem blight disease caused by Phomopsis asparagi. However, the mechanisms underlying this resistance are not understood and no transcriptomic or genetic resources are available for this species. De novo transcriptome sequencing of A. officinalis and A. kiusianus stems was performed 24 h after inoculation with P. asparagi. In total, 35,259 and 36,321 transcripts were annotated in A. officinalis and A. kiusianus, respectively. 1,027 up-regulated and 752 down-regulated transcripts were differentially expressed in the two Asparagus species. RNA sequencing data were validated using quantitative real-time reverse transcription PCR. Several defense-related genes including peroxidase 4, cationic peroxidase SPC4-like, pathogenesis-related protein-1-like, and jasmonic acid biosynthesis and signaling-related genes including phospholipase D alpha 1, 12-oxophytodienoate reductase and jasmonate-induced protein 23 KD were up-regulated in A. kiusianus relative to A. officinalis. In addition, infected A. kiusianuns exhibited a substantial increase in jasmonic acid and methyl jasmonate relative to A. officinalis. Peroxidase activity was significantly elevated in infected A. kiusianus compared with infected A. officinalis. Our transcriptomic database provides a resource for identifying novel genes and molecular markers-associated with Phomopsis disease resistance and will facilitate breeding and improvement of cultivated asparagus varieties.
Highlights
Asparagus officinalis L., a dioecious species of the family Asparagaceae, is an economically important horticultural crop worldwide because of its culinary and medicinal properties
Asparagus stem blight, which is caused by P. asparagi, is a serious disease that affects asparagus production worldwide, and there is an urgent need to produce asparagus cultivars with strong resistance to this disease
After artificial inoculation with P. asparagi, A. kiusianus, a wild relative of cultivated A. officinalis, exhibited significantly (P < 0.001) reduced disease severity compared with A. officinalis (Fig. 1), consistent with a previous study examining disease in these Asparagus species[4]
Summary
Asparagus officinalis L., a dioecious species of the family Asparagaceae, is an economically important horticultural crop worldwide because of its culinary and medicinal properties. Wild Asparagus species represent a potential genetic resource for the development of disease-resistant Asparagus germplasm with desirable physiological attributes. Several wild Asparagus species exhibited a strong disease resistance phenotype in previous studies, but production of interspecific hybrids by crossing with cultivated A. officinalis was hampered by the genetic distance between species[7]. Further development of Asparagus genetic resources and research to discover novel disease resistance alleles will help to improve germplasm utilization and facilitate breeding of new asparagus varieties. To identify the broad transcriptional network-associated with Phomopsis disease resistance in Asparagus, we conducted transcriptome analysis of susceptible A. officinalis and resistant wild A. kiusianus stems 24 h after inoculation with P. asparagi or mock inoculation with sterile distilled water (SDW). Our transcriptome dataset is a valuable and unique resource that will facilitate future functional genetics studies and molecular marker development for asparagus breeding
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
