Ozone-Induced Rice Grain Yield Loss Is Triggered via a Change in Panicle Morphology That Is Controlled by ABERRANT PANICLE ORGANIZATION 1 Gene

Abstract

Rice grain yield is predicted to decrease in the future because of an increase in tropospheric ozone concentration. However, the underlying mechanisms are unclear. Here, we investigated the responses to ozone of two rice (Oryza Sativa L.) cultivars, Sasanishiki and Habataki. Sasanishiki showed ozone-induced leaf injury, but no grain yield loss. By contrast, Habataki showed grain yield loss with minimal leaf injury. A QTL associated with grain yield loss caused by ozone was identified in Sasanishiki/Habataki chromosome segment substitution lines and included the ABERRANT PANICLE ORGANIZATION 1 (APO1) gene. The Habataki allele of the APO1 locus in a near-isogenic line also resulted in grain yield loss upon ozone exposure, suggesting APO1 involvement in ozone-induced yield loss. Only a few differences in the APO1 amino acid sequences were detected between the cultivars, but the APO1 transcript level was oppositely regulated by ozone exposure: i.e., it increased in Sasanishiki and decreased in Habataki. Interestingly, the levels of some phytohormones (jasmonic acid, jasmonoyl-L-isoleucine, and abscisic acid) known to be involved in attenuation of ozone-induced leaf injury tended to decrease in Sasanishiki but to increase in Habataki upon ozone exposure. These data indicate that ozone-induced grain yield loss in Habataki is caused by a reduction in the APO1 transcript level through an increase in the levels of phytohormones that reduce leaf damage.

Elevated O3 and TYLCV Infection Reduce the Suitability of Tomato as a Host for the Whitefly Bemisia tabaci

“…Although much is known about the effects of elevated O 3 on viruses and insect pests, little is known about the effects of elevated O 3 and virus-infected plant on the performance of insect pests. O 3 is highly phytotoxic [54,55,56,57]. In the current study, elevated O 3 significantly reduced the fresh biomass and height of Wt tomato plants and also reduced their free amino acid and soluble sugar contents.…”

Phytohormones in red seaweeds: a technical review of methods for analysis and a consideration of genomic data

“…Therefore, it is not difficult to increase the number of samples to acquire much information. Furthermore, variation in the data set is minimized, and The scheme represents the procedure of purification and fractionation of phytohormones reported in Tsukahara et al (2015) and Mikami et al (2016). Ten hormones were fractionated into three fractions.…”

“…The remaining hormones were eluted from the anion exchange cartridge as the acidic fraction and successively analyzed by LC-MS method 1. For the detailed procedure of fractionation and LC-MS methods, see Tsukahara et al (2015) and Mikami et al (2016). An example of sequential analysis of five hormones in an acidic fraction in a single run using the LC-MS method 1.…”

“…An example of sequential analysis of five hormones in an acidic fraction in a single run using the LC-MS method 1. Phytohormones were extracted from flower buds (~20 mg) of Arabidopsis thaliana by the method described in Tsukahara et al (2015). The single run, using the LC-MS method 1 with a gradient of solvent, was divided into more than five segments.…”

“…For example, Tsukahara et al (2015) initially hypothesized that differences in auxin content were involved in the observed yield differences between two rice (Oryza sativa L.) cultivars exposed to ozone. However, they found that JA was involved in the ozone response instead of IAA.…”