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

Tsukahara K, Sawada H, Kohno Y, Matsuura T, Mori IC, Terao T, Ioki M, Tamaoki M - PLoS ONE (2015)

Bottom Line: 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.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.

View Article: PubMed Central - PubMed

Affiliation: Center for Environmental Biology and Ecosystem, National Institute for Environmental Studies, Tsukuba, Ibaraki, 305-8506, Japan; Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki, 305-8577, Japan.

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.

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Relative levels of APO1 transcript in different organs.(A) APO1 transcript levels in the fourth leaf, young panicle (10 days before heading), root, and an inflorescence meristem (IM; 23 days before heading). (B) Ozone-induced changes in the APO1 transcript level in inflorescence meristems of Sasanishiki (Sasa) and Habataki (Haba). Values are mean ± SD (n = 3). AA, ambient air; O3, elevated ozone. n.s., not significant; **P<0.05 (Student’s t-test, A). Bars topped by the same letters are not significantly different (Tukey’s HSD test, P<0.05, B).
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pone.0123308.g006: Relative levels of APO1 transcript in different organs.(A) APO1 transcript levels in the fourth leaf, young panicle (10 days before heading), root, and an inflorescence meristem (IM; 23 days before heading). (B) Ozone-induced changes in the APO1 transcript level in inflorescence meristems of Sasanishiki (Sasa) and Habataki (Haba). Values are mean ± SD (n = 3). AA, ambient air; O3, elevated ozone. n.s., not significant; **P<0.05 (Student’s t-test, A). Bars topped by the same letters are not significantly different (Tukey’s HSD test, P<0.05, B).

Mentions: We have previously reported that the level of APO1 transcripts in young panicles was suppressed by ozone in Habataki but increased in Sasanishiki [18]. To understand the APO1 expression pattern in more detail, we compared it in several organs in the two cultivars. The APO1 transcript was detected in the young panicles, roots, and inflorescence meristems, but not in the leaf blades; the expression level was higher in Habataki than in Sasanishiki (Fig 6A). In Habataki, remarkably high APO1 expression was observed in inflorescence meristems, where it was 17 times that in young panicles. Ozone treatment reduced the APO1 transcript level in inflorescence meristems of Habataki to one-seventh of that under ambient air, but increased the transcript level in Sasanishiki by approximately 100%, although this increase did not reach statistical significance (Fig 6B, P = 0.076). These findings are in line with our previous report for young panicles [18]. Furthermore, the APO1 transcript level in SHA422-1.1 was 5-fold higher than that in SHA422-1.3 under NF condition, but that in both lines were decreased by ozone treatment (Fig C in S1 File).


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

Tsukahara K, Sawada H, Kohno Y, Matsuura T, Mori IC, Terao T, Ioki M, Tamaoki M - PLoS ONE (2015)

Relative levels of APO1 transcript in different organs.(A) APO1 transcript levels in the fourth leaf, young panicle (10 days before heading), root, and an inflorescence meristem (IM; 23 days before heading). (B) Ozone-induced changes in the APO1 transcript level in inflorescence meristems of Sasanishiki (Sasa) and Habataki (Haba). Values are mean ± SD (n = 3). AA, ambient air; O3, elevated ozone. n.s., not significant; **P<0.05 (Student’s t-test, A). Bars topped by the same letters are not significantly different (Tukey’s HSD test, P<0.05, B).
© Copyright Policy
Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC4414449&req=5

pone.0123308.g006: Relative levels of APO1 transcript in different organs.(A) APO1 transcript levels in the fourth leaf, young panicle (10 days before heading), root, and an inflorescence meristem (IM; 23 days before heading). (B) Ozone-induced changes in the APO1 transcript level in inflorescence meristems of Sasanishiki (Sasa) and Habataki (Haba). Values are mean ± SD (n = 3). AA, ambient air; O3, elevated ozone. n.s., not significant; **P<0.05 (Student’s t-test, A). Bars topped by the same letters are not significantly different (Tukey’s HSD test, P<0.05, B).
Mentions: We have previously reported that the level of APO1 transcripts in young panicles was suppressed by ozone in Habataki but increased in Sasanishiki [18]. To understand the APO1 expression pattern in more detail, we compared it in several organs in the two cultivars. The APO1 transcript was detected in the young panicles, roots, and inflorescence meristems, but not in the leaf blades; the expression level was higher in Habataki than in Sasanishiki (Fig 6A). In Habataki, remarkably high APO1 expression was observed in inflorescence meristems, where it was 17 times that in young panicles. Ozone treatment reduced the APO1 transcript level in inflorescence meristems of Habataki to one-seventh of that under ambient air, but increased the transcript level in Sasanishiki by approximately 100%, although this increase did not reach statistical significance (Fig 6B, P = 0.076). These findings are in line with our previous report for young panicles [18]. Furthermore, the APO1 transcript level in SHA422-1.1 was 5-fold higher than that in SHA422-1.3 under NF condition, but that in both lines were decreased by ozone treatment (Fig C in S1 File).

Bottom Line: 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.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.

View Article: PubMed Central - PubMed

Affiliation: Center for Environmental Biology and Ecosystem, National Institute for Environmental Studies, Tsukuba, Ibaraki, 305-8506, Japan; Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki, 305-8577, Japan.

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.

Show MeSH
Related in: MedlinePlus