Abstract
Obligate root holoparasite Phelipanche aegyptiaca is an agricultural pest, which infests its hosts and feeds on the sap, subsequently damaging crop yield and quality. Its notoriously viable seed bank may serve as an ideal pest control target. The phytohormone abscisic acid (ABA) was shown to regulate P. aegyptiaca seed dormancy following strigolactones germination stimulus. Transcription analysis of signaling components revealed five ABA receptors and two co-receptors (PP2C). Transcription of lower ABA-affinity subfamily III receptors was absent in all tested stages of P. aegyptiaca development and parasitism stages. P. aegyptiaca ABA receptors interacted with the PP2Cs, and inhibited their activity in an ABA-dependent manner. Moreover, sequence analysis revealed multiple alleles in two P. aegyptiaca ABA receptors, with many non-synonymous mutations. Functional analysis of selected receptor alleles identified a variant with substantially decreased inhibitory effect of PP2Cs activity in-vitro. These results provide evidence that P. aegyptiaca is capable of biochemically perceiving ABA. In light of the possible involvement of ABA in parasitic activities, the discovery of active ABA receptors and PP2Cs could provide a new biochemical target for the agricultural management of P. aegyptiaca. Furthermore, the potential genetic loss of subfamily III receptors in this species, could position P. aegyptiaca as a valuable model in the ABA perception research field.
Highlights
The obligate root holoparasite weed Phelipanche aegyptiaca (Egyptian broomrape), is a species from the Orobanchaceae family, which includes some of the most agriculturally damaging weeds[1,2,3]
The basis of the biochemical response to abscisic acid (ABA) is facilitated by an interaction between ABA and its receptor, followed by the ABA-receptor inhibitory effect on a co-receptor (PP2CA)
Through characterization of the plant’s ABA receptors and co-receptors and comparison with homologous autotrophic angiosperm genes, we propose a possible deterioration of the P. aegyptiaca ABA perception mechanism
Summary
The obligate root holoparasite weed Phelipanche aegyptiaca (Egyptian broomrape), is a species from the Orobanchaceae family, which includes some of the most agriculturally damaging weeds[1,2,3]. Germination of P. aegyptiaca and other obligate Orobanchaceae parasites requires strigolactones, stimuli derived from the host plant[6]. ABA elicits its effect by binding pyrabactin resistance1/PYR1-like/regulatory component of ABA receptor (PYR/PYL/RCAR) ABA receptors in a large and conserved hydrophobic pocket, which changes the conformation of two highly conserved loops located in the outer periphery of the pocket[11,12,13]. Both loops, the “gate” and the “latch”, move towards the ligand and in doing so “cover” the pocket cavity[13]. PYR1 K59 H60 F61 I62 K63 V83 I84 S85 G86 L87 P88 A89 S92 E94 F108 I110 H115 R116 L117 Y120 E141 S142 V145 P148 N151 D155 M158 F159 A160 V163 V164 L166 N167
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
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.
