Encouraging news stories have appeared in recent months on the possible benefits of using peptides in the fight against HLB. Peptides, small groups of linked amino acids, have many functions, including acting on pathogens.
As researchers continue to investigate the role of peptides in the fight against HLB, they are also looking for the most effective delivery method of these HLB therapeutics.
Harold Browning, chief science officer at Premier Citrus ApZ, shared potential peptide delivery methods during the Citrus Research and Development Foundation (CRDF) virtual peptide seminar on Nov. 18.
According to Browning, conventional foliar spraying has a long history in citrus and is the most sought after way to deliver therapeutics. Foliar spraying is fast, economical and effective when targeting organisms that reside on the surface of the plant. For this reason, foliar-applied peptides that bind to specific receptors on plant cells and cause specific plant responses, such as an immune response, would be a great benefit.
However, foliar-applied therapeutics have shown limited success due to not enough materials getting absorbed by the plant. Because of this, other delivery methods are being researched. Trials investigating delivery via trunk injection are in progress.
Although trunk injection seems to be an ideal method to deliver peptides, typical trunk injection is labor-intensive and costly. It can also cause entry port damage, impacting the long-term viability of the tree. Currently, alternative systems of trunk injection are being developed to overcome these challenges.
Laser etching to deliver therapeutics is also being investigated. Premier Citrus is working on an ApZ laser-based technology to fight against HLB. The technology makes small indentations on citrus leaves, allowing the therapeutic materials to enter the phloem quickly and efficiently.
“The whole purpose of this is to open an avenue for direct absorption,” Browning says.
Trials for this technology are underway in commercial citrus plantings across Florida and have shown promising results.
This article was written by Ashley Robinson, AgNet Media communications intern in Gainesville, Florida.