Comparative analysis of sorghum (C4) and rice (C3) plant headspace volatiles induced by artificial herbivory

ABSTRACT

Acute stress responses include release of defensive volatiles from herbivore-attacked plants. Here we used two closely related monocot species, rice as a representative C3 plant, and sorghum as a representative C4 plant, and compared their basal and stress-induced headspace volatile organic compounds (VOCs). Although both plants emitted similar types of constitutive and induced VOCs, in agreement with the close phylogenetic relationship of the species, several mono- and sesquiterpenes have been significantly less abundant in headspace of sorghum relative to rice. Furthermore, in spite of generally lower VOC levels, some compounds, such as the green leaf volatile (Z)-3-hexenyl acetate and homoterpene DMNT, remained relatively high in the sorghum headspace, suggesting that a separate mechanism for dispersal of these compounds may have evolved in this plant. Finally, a variable amount of several VOCs among three sorghum cultivars of different geographical origins suggested that release of VOCs could be used as a valuable resource for the increase of sorghum resistance against herbivores.

ONE SENTENCE SUMMARY

This paper shows how genetically related plants with similar volatile toolboxes define their own species identity in the ecological space.

KEYWORDS:

• Volatile organic compounds
• rice
• sorghum
• indirect defense
• herbivores
• terpenoids

Acknowledgments

We thank Japan Society for the Promotion of Science (JSPS) for supporting of C.O. travels to Japan under auspices of the Africa-Asia Science platform program. We acknowledge A. Miyake (Okayama University) for help with VOC sampling and W. Sakamoto (Okayama University) for provision of sorghum resources. This research was supported by grants from JSPS KAKENHI Grant Numbers P13379, P20103, 13F03379, 20F20103, and 21H02196; Ohara Foundation in Japan; and MEXT Joint Research Program implemented at Okayama University Institute of Plant Science and Resources.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Author contributions

C.O., I.S.S., D.W., S.T.D., Y.H., D.A.O, T.S. and I.G. performed experiments and analyzed data; C.O., I.S.S. and I.G. wrote the main manuscript text; A.K.T., A.M.N and I.G. designed and guided research. All authors reviewed the manuscript.

Supplementary material

Supplemental data for this article can be accessed online at https://doi.org/10.1080/15592324.2023.2243064

Additional information

Funding

The work was supported by the Japan Society for the Promotion of Science [13F03379, 20F20103, 21H02196]; Japan Society for the Promotion of Science [P20103]; MEXT Joint Research Program Japan Society for the Promotion of Science [P 13379]; Ohara Foundation in Japan .