Jasmonate signaling constraints regrowth in Nicotiana attenuata.

ZAVALA, J.A.; BALDWIN, I.T.

PLANT, CELL AND ENVIRONMENT (PRINT)

Año: 2006 vol. 29 p. 1751 - 1760

0140-7791

Because traits conferring resistance on herbivores can reduce fitness-associated traits, trade-offs may occur between tolerance and resistance responses. We examined these trade-offs in genotypes of Nicotiana attenuata that were transformed to silence trypsin proteinase inhibitor (TPI) production (AS-Natpi), an antiherbivore defense associated with (14%) reductions in seed production, and the jasmonate signal cascade that elicits these defenses (ASNalox3), by measuring stalk and axillary branch growth and seed production after two defoliation regimes and Manduca sexta larval attack to bottom or middle and top stalk leaves. Larval attack and defoliation at middle and top leaves depressed seed production and increased axillary branching more than at bottom leaves. ASNalox3 and ASNatpi plants produced significantly longer (two- to fourfold) branches than did wild-type (WT) plants, results that are consistent with resource-based trade-offs between resistance and regrowth. Methyl jasmonate (MeJA) treatment of ASNalox3 plants restored WT branch growth, suggesting that jasmonic acid (JA) signalling suppresses regrowth and contributes to apical dominance. These results are consistent with the existence of JA- and resource-mediated trade-offs between regrowth and herbivore resistance traits.Nicotiana attenuata that were transformed to silence trypsin proteinase inhibitor (TPI) production (AS-Natpi), an antiherbivore defense associated with (14%) reductions in seed production, and the jasmonate signal cascade that elicits these defenses (ASNalox3), by measuring stalk and axillary branch growth and seed production after two defoliation regimes and Manduca sexta larval attack to bottom or middle and top stalk leaves. Larval attack and defoliation at middle and top leaves depressed seed production and increased axillary branching more than at bottom leaves. ASNalox3 and ASNatpi plants produced significantly longer (two- to fourfold) branches than did wild-type (WT) plants, results that are consistent with resource-based trade-offs between resistance and regrowth. Methyl jasmonate (MeJA) treatment of ASNalox3 plants restored WT branch growth, suggesting that jasmonic acid (JA) signalling suppresses regrowth and contributes to apical dominance. These results are consistent with the existence of JA- and resource-mediated trade-offs between regrowth and herbivore resistance traits.