We study the effect of intersegment interactions on the effective bendin and stretching moduli of a semiflexible polymer chain with a finite s tretching modulus. For an interaction potential of a screened Debye-Huckel type, renormalization of the strecching modulus is derived on the same level of approximation as the celebrated Odijk-Skolnick-Fixman result for the bending modulus. The presence of mesoscopic intersegment interaction potentials couples the bending and strecching moduli in a manner different from that predicted by the macroscopic elasticity theory. We thus advocate a fundamental change in the perspective regarding the dependence of elastic moduli of a flexible polyelectrolyte on the ionic conditions:stretchability. The theory presented here and its consequences compare facvorably with recent experments on DNA bending and styretching at not too low salt conditions
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