Abstract
The global climate change is leading to increased frequency of heatwaves with crops getting exposed to extreme temperature events. Such temperature spikes during the reproductive stage of plant development can harm crop fertility and productivity. Here we report the response of short-term heat stress events on the pollen and pistil tissues in a commercially grown cultivar of Brassica napus. Our data reveals that short-term temperature spikes not only affect pollen fitness but also impair the ability of the pistil to support pollen germination and pollen tube growth and that the heat stress sensitivity of pistil can have severe consequences for seed set and yield. Comparative transcriptome profiling of non-stressed and heat-stressed (40°C for 30 min) pollen and pistil (stigma + style) highlighted the underlying cellular mechanisms involved in heat stress response in these reproductive tissues. In pollen, cell wall organization and cellular transport-related genes possibly regulate pollen fitness under heat stress while the heat stress-induced repression of transcription factor encoding transcripts is a feature of the pistil response. Overall, high temperature altered the expression of genes involved in protein processing, regulation of transcription, pollen-pistil interactions, and misregulation of cellular organization, transport, and metabolism. Our results show that short episodes of high-temperature exposure in B. napus modulate key regulatory pathways disrupted reproductive processes, ultimately translating to yield loss. Further investigations on the genes and networks identified in the present study pave a way toward genetic improvement of the thermotolerance and reproductive performance of B. napus varieties.
Highlights
Brassica napus L. is the third most important oilseed crop produced globally
To address gaps in our understanding of effects of short-term heat stress events on reproduction, we investigated the effects of heat stress at 40◦C for 4 h on pollen-pistil interactions by performing reciprocal crosses between non-stressed, and heatstressed pollen and pistil
The higher rate of seed set in NS pistil × HS pollen indicate that even ∼25% viable pollen grains were sufficient to fertilize almost all of the ovules
Summary
Brassica napus L. (canola/rapeseed) is the third most important oilseed crop produced globally. Since even short-lived high-temperature spikes can have significant adverse effects on reproductive success, it is crucial to understand the underlying molecular basis short-term heat stress response during pollen-pistil interactions (Frank et al, 2009; Begcy et al, 2019). There is a recent focus on the female reproductive organ sensitivity to high temperature in crops like sorghum, rice, maize, wheat, and tomato (Gonzalo et al, 2020; Jagadish, 2020; Lohani et al, 2020b). The outcomes of these studies reveal a considerable variation in heat stress response of pistil (stigma or ovary) across crops. Our RNA-seq analysis highlights differential regulation of specific genes involved in pollen cell wall organization, water channel activity, ROS metabolism, fatty acid metabolism, phenylpropanoid biosynthesis, and genes involved in pollenpistil interactions
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.
