In the world of horticulture, a tiny genetic tweak can lead to a big change, as evidenced by a recent study published in the Horticultural Plant Journal. Researchers, led by Yuhao Gao from the College of Agriculture and Biotechnology at Zhejiang University, have unraveled the genetic secrets behind the vibrant red color of certain pear varieties, a discovery that could have significant implications for the fruit breeding industry.
The study focused on ‘Hongzaosu’, a red pear cultivar that originated from a bud sport of the green pear ‘Zaosu’. Bud sports are sudden genetic mutations that occur in plants, often leading to visible changes in the plant’s appearance. In this case, the mutation resulted in the accumulation of anthocyanins, the pigments responsible for the red color in many fruits and vegetables.
The research team constructed a new genetic map using a population derived from a cross between ‘Yuluxiang’ and ‘Hongzaosu’. This map led them to a crucial gene, PpBBX24, which they found to be a repressor of anthocyanin biosynthesis in pear. “Most red pear cultivars that accumulate anthocyanins originated from somatic variation and are termed as bud sports. Our study reveals that a 14 bp deletion in the third exon of PpBBX24 in ‘Hongzaosu’ results in premature termination of protein translation,” Gao explained. This truncated protein, instead of repressing anthocyanin production, actually promotes it by activating the transcription of other genes involved in anthocyanin biosynthesis.
The team also discovered three independent variations in the BBX24 coding region in other pear bud sports and their progeny, all of which accumulate anthocyanins. This suggests that these variations could be a common mechanism behind the red coloration in these pears.
But the discoveries didn’t stop there. The researchers also assembled the genome of ‘Hongzaosu’ using both long-read and short-read sequences. By combining genomic and transcriptomic data, they observed allele-specific expression of PpMYB110a in the fruit skin of ‘Hongzaosu’, likely caused by a large variation in the promoter.
So, what does this mean for the future of pear breeding and the horticulture industry as a whole? “This work enhances our understanding of coloration in red pears and provides a novel genomic resource for further studies on ‘Hongzaosu’ pear,” Gao said. The findings could potentially lead to more efficient and targeted breeding programs, resulting in new pear varieties with desirable traits, such as enhanced color and potentially improved nutritional value.
Moreover, the study’s focus on bud sports and their genetic underpinnings could open up new avenues for research into other plant species. As our understanding of these genetic mechanisms grows, so too will our ability to develop new and improved crop varieties, benefiting both growers and consumers alike.
In the ever-evolving world of horticulture, this research is a testament to the power of genetic exploration and its potential to shape the future of agriculture. As we continue to unravel the complexities of the plant genome, we open up new possibilities for innovation and growth in the horticulture industry.